This document provides instructions for exercises examining the morphology of insects including cockroaches, mosquitoes, sandflies, biting midges, and blackflies. It describes the procedures for examining both external and internal anatomy of these insects as well as their immature stages. Key structures are defined for each insect group, such as the segmented body, antennae, wings, legs, mouthparts, circulatory and digestive systems. The exercises aim to teach insect morphology and aid in identification of specimens.

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Exercise 1.
Insect Morphology
A basic knowledge of form and
structure of insects is necessary in order to
understand the modifications that will be
encountered in more specialized insects
particularly parasitic ones. An understanding of
the terms applied to the external and internal
anatomy of insects is also imperative and
utilized as key findings in identification of
specimens.
In this exercise, a cockroach will be
used due to the fact that it is a generalized insect
with basic morphology and primitive nature.
Materials:
Adult cockroaches
Jar with cap
Scalpel with scalpel blade
Tissue forceps
Dissecting scissors
Dissecting pan/ paraffin plate
Magnifying lens
Cotton
Chloroform (or any suitable insecticide)
Colored pins
Mask and gloves
Procedure:
1. Place the adult cockroaches inside the jar
with cap. Be careful kin handling
cockroaches to avoid distortion of the
external morphology of the insect as well as
this can deliver a painful bite.
2. Wet the cotton with chloroform or
insecticide and place it inside the jar
together with the cockroaches. Leave this
for about five minutes until the cockroaches
are killed.
3. Using the dissecting pan and dissecting set,
examine the following structures. A
magnifying lens may be used to aid the
examination of very small structures.
External Anatomy
1. Note that the body is divided into three main
parts: head, thorax and abdomen.
2. Examine the head. Locate the antenna,
compound eyes and simple eyes (ocelli).
The frons refer to the front of the head
which bears the antenna and the ocelli. At
the top of the head is the vertex. At each
side of the head is the gena located below
the compound eyes. Below the frons is the
clypeus, the part which holds the labrum (to
be examined under the section Mouthparts).
3. Study the thorax. Note that it is subdivided
into three segments, prothorax, mesothorax
and metathorax. The dorsal portion of the
thorax is known as the notum. Note that the
pronotum (dorsal portion of the prothorax)
overhangs the head. Observe the wings
which also arises from this segment. How
many pairs of wings are there? Which
segment of the thorax bears the forewing or
tegmina? How about the hindwing. Would
you be able to differentiate the forewing
from the hindwing. Note that the wings are
supported by branching structures called
veins. The arrangement of these veins is
significant with regards to the identification
of species in most cases. Insects are
characterized by having three pairs of legs
arising from each segment of the thorax.
Carefully remove the legs. Observe the
segments of the legs, from proximal to
distal, namely, coxa, trochanter,femur, tibia
and tarsus ( being composed of around 5
joints). Note that the last tarsal segment is
provided with a pair of claws between which
is an empodium, pulvilli or ariolum (in the
case of the cockroach). This consists of a
pad and a spine or a bristle.

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4. Examine the abdomen. Note that it is clearly
segmented and relatively membranous
compared to the thorax. How many
segments are there? Identify the anal plates
and the cerci which can be noted in both
sexes. Examine the ovipositor in the female
and the anal stylets in the male specimens.
Mouthparts
1. Remove the head from the head from the
specimen. Note that the head is separated
from the thorax by a neck called cervix.
Examine it from all angles, taking note of
the relative positions of the mouthparts.
2. Hanging from the clypeus is the hinged
labrum or upper lip. In some specimen a
small membranous structure may be found
on the underside of the labrum, the
epipharynx, which serve as the organ of
taste. It is frequently encountered fused
forming the labrum-epipharynx.
3. Using a pin, carefully try to lift the labrum
to expose a pair of heavy jaws called
mandibles, both of which bear teeth at the
inner edge and movable laterally.
4. Try to abduct the mandible to expose the
pair of maxillae. Some specimen will have
more than one pair of maxilla.
5. The most posteriorly situated mouthpart is
the labium or the lower lip.
6. Both the maxillae and labium bears jointed
sections called palps, which are sensory in
function.
7. Between the maxillae and the labium is a
median, fleshy, tongue-like organ called
hypopharynx.
Internal Anatomy
Remove all the legs from the base. Cut along the
lateral sides with a pair of fine-pointed scissors.
Carefully reflect the dorsal flap so as to expose
the internal organs.
1. The respiratory system of insects is made up
of many branching tubes. The tube start at
openings called spiracles, which opens to
the air at the side of the insects. Air enters
the cockroach body through the spiracle.
Inside the body, the larger tubes are called
trachea. Trachea is found close to the
cockroach’s dorsal vessel or heart. The
trachea branch-out into smaller tubes called
tracheoles. Tracheoles surround all of the
insects’ organs and tissues. They supply the
tissues with oxygen and remove the carbon
dioxide.
2. Insects store fat, protein, and excretory
products in their fat bodies. Insects have an
open circulatory system. The dorsal vessel is
a thin, segmented tube, closed at the hind
end of the insect. At the front end of the
cockroach, the dorsal vessel opens into the
body cavity that surrounds all the organs.
Insects have hemolymph, instead of blood.
Each segment, or chamber, of the dorsal
vessel has openings that gather hemolymph
from the body cavity. The dorsal vessel
works like a heart and is the main vessel of
the circulatory system of an insect. It pumps
hemolymph towards the head and into the
body cavity. In comparison to insects,
humans have a closed circulatory system.
The blood flows through blood vessels to
reach all parts of the body.
3. Gently remove the internal organs to a petri
dish half-filled with water. Gently agitate
the organs in the water to remove adherent
adipose tissue. Identify the structure
comprising the digestive tract. It is generally
composed of the stomodaeum, mesenteron
or proctodaeum. The stomodaeum is
composed of the buccal cavity with salivary
glands, crop, gizzard and gatric sacs. The
crop is where undigested food is temporarily
stored. The gizzard is a muscular stomach
with sharp teeth-like structures that grinds
the food into smaller pieces. The gastric
sacks contain bacteria that the cockroach
uses to digest its food. The mesenteron
forms the midgut (ileum). Most of the
absorption of the food’s nutrients takes place
in the midgut At its posterior end are the
malphigian tubes, which have excretory
functions. These organs also regulate the
balance of water and salts in the cockroach’s
body. The proctodaeum consists of the
hindgut and rectum. Reabsorption of water,
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occurs here. The remaining wastes leave the
body through the rectum, which is also part
of the excretory system.
4. The cockroaches’ nerve cord is part of its
nervous system. The nerve cord is shiny and
white and consists of two parallel strands
running close together along the ventral or
underside of the cockroach. The nerve
strands join together at each body segment
to form lumps or ganglia. Nerves radiate out
from each ganglion into each muscles and
sense organs.
Wing Venation
The wings are composed of a thin membrane. As
previously mentioned, these are supported by
fibers called veins which run from the base to
the apex of the wing and that the arrangement or
pattern is pertinent to identification of
specimens. This arrangement is called venation.
The main veins of the wings are: costa
(thickened anterior vein); subcosta (vein
immediately below the costa).

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Exercise 2
Mosquitoes
Mosquitoes belong to the family Culicidae,
which are slender Nematocera, with small
spherical heads with contiguous/ dichoptic
compound eyes and long legs. The antenna bears
14-15 segments and is plumose in males. The
mouthpart is highly developed into a sucking
apparatus, commonly called, proboscis. The
abdomen is elongate and the thorax is wedge-
shaped, with the broad end dorsad.
Because of the great importance of mosquitoes
as vectors of various infectious agents to man
and animals, they have been subjected to further
detailed examination and classification.
Mattingley (1973) has provided keys in the
identification of subfamilies and genera of
Culicidae, but for veterinary medicine,
mosquitoes are only divided into two groups,
Culicine and Anopheline mosquitoes based on
the major differences in life cycle, behavior and
health importance.
In this exercise, preserved gross and mounted
specimens of mosquitoes, its parts and its
immature stages will be examined in order to aid
the student in studying the special
morphological features of mosquitoes and its
immature forms and classify them into two
groups mentioned above.
1. Examine the head of mosquitoes. Note that
it is roughly spherical and that the
compound eyes are nearly contiguous or
dichoptic. Examine the long antenna
composed of 14-15 segments.
2. Study the mouthparts developed into a
proboscis. Note that it is composed of
labium, labrum-epipharynx, hypopharynx,
mandible and the first maxilla, however,
unlike other insects, these are modified into
slender and long parts which work their way
to penetrate the skin and suck blood from
the host. The labium is deeply grooved
dorsally to hold the other stylet-like organs
and terminates into a pair of lobes called
labella. The labrum-epipharynx is the
strongest stylet deeply grooved ventrally.
Mandibles are needle-like however in the
male they are greatly reduced or absent. The
1st
maxilla are a pair of flattened stylets with
serrated distal tips while the maxillary palps
composed of 4 segments are held stiff on
either side of the proboscis. The single
hypopharynx is located median.
3. Examine the fused thoracic segments. The
anterior plate on the dorsum of the thorax is
called scutum, smaller posterior plate behind
it is the scutellum. Note that the scutellum of
Culicine mosquito is tri-lobed while that of
Anopheline is evenly curved. Next to the
scutellum is a dome-shaped plate called
post-scutellum.
4. Study the wings. Note that it is long, narrow
and folded flat over the abdomen during
rest. Examine the wings under the
microscope. What structures cover the veins
and lines the margin of the wings? These are
also located on the abdomen, legs and
proboscis of the same species. Note that in
most dipterans, the posterior pair is reduced
as a pair of balancers or halteres.
5. Note the 3 pairs of long, slender legs.
Identify the segments. Examine the 5th
tarsal
segment. Note the bristle-like empodium
between the claws.

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6. Examine the tip of the abdomen. Note the
cerci and postgenital plate in females and
claspers in males.
7. Aside from the structures located on the
terminal end of the abdomen. The sex of the
mosquito may be identified even if only the
head of the specimen is provided. Examine
the mounted specimen. Is it male or female?
As mentioned above, the antenna of male
species is plumose (have more bristles
arising from it) while for the females it is
pilose (less bristles). The maxillary palps of
male Culicine mosquitoes are as long as the
proboscis compared to the female which are
relatively shorter. However, this dimorphism
is not exhibited by Anopheline mosquitoes,
rather the male’s maxillary palps are
clubbed terminally and the female have
palps as long as the proboscis.
8. The eggs are usually laid on water or on
floating matter and each species have special
requirements which are restrictive. Some
species lay eggs on rain water, stagnant or
vessels of water, at the edge of streams or
even in salt water. These may be deposited
en masse called egg-rafts (Culex) or singly
(Anopheles and Aedes). Egg rafts are
arranged vertically with their anterior end
towards water, while anopheline eggs are
boat shaped with frilled edges and provided
with a float on either side.
9. The larva bears a well developed head, a
distinct thorax and abdomen. The head is
provided with eyes, antenna and several
hairs. Note that the head is capable of
turning around 180 degrees. Examine the
Culicine larva which is provided with well-
developed siphon tube arising from the
dorsal aspect of the 8th
and 9th
abdominal
segments and surrounds the stigmata. This is
not present in Anopheline larva. However,
Anopheline larva is provided with palmate
hairs on the abdomen with which they are
capable of clinging onto the surface of the
water. With such structures, the Culicine
larva is able to hand down into the water
while the Anopheline larva lie against the
surface. The 10th
segment bears tracheal
gills found in well-developed forms of
Aedes that feed under water.
10. The pupa has a rounded body which consists
of the head and the thorax, an elongate
abdomen flattened dorsoventrally and flexed
under the body. A pair of breathing or
respiratory trumpets are located on the
dorsal aspect of the thorax attached to the
lateral stigmata through which the pupa
breathes at the surface of the water. Note
that the breathing trumpets of Culicine
mosquitoes are long and narrow while that
of Anopheline are short and broad.

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Exercise 3
Sandflies, Biting Midges and Blackflies
Sandflies, biting midges and blackflies are small
blood-sucking flies, measuring 1-5 mm in
length.
Sandflies belong to the Family Psychodidae.
Commonly called owl midges. They are small,
moth-like flies with their bodies and wings
covered with hairs. The antenna is long with
sixteen segments and has a beaded appearance.
The palps are recurved and hairy. Phlebotomus
flies are important vectors in the transmission of
Leishmaniasis or sandfly fever.
Biting midges of the genus Culicoides belong to
the family Ceratopogonidae. These are very
minute insects also called punkies and no-see-
ums. Their mouthpart is small and short
proboscis, adapted for sucking blood with
mandibles acting as scissors. The antenna of
biting midges is long and exhibits the same
sexual dimorphism as that of Culicine
mosquitoes. The thorax is humped over the
head. The wings are spotted and unlike
mosquitoes, they do not bear scales, rather hairs.
The anterior wing veins are more prominent than
the posterior ones, enclosing the area called 1st
and 2nd
radial cells. The median vein is forked
with branches extending up to the margin of the
wing.
Blackflies (Simulium spp.) belong to the family
Simuliidae. These are also commonly called
buffalo gnats. Note that the antenna is very short
with 11 segments and compound eyes of females
are dichoptic while that of male is holoptic. The
thorax is also humped over the head and the
proboscis is short. The wings are also broad,
however they are not spotted, neither having
scales nor hairy, except for bristles found only
on the thick anterior veins. The other veins are
poorly defined. The body is covered with short
hairs.
At the end of this exercise, it is expected that
students should be able to differentiate one
species from the other by taking note of the
morphologic features of each insect.

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Exercise 4
Flies
Memebers belonging to subfamily Muscidae are
commonly called “flies” or from an
entomologists view point, they are exclusively
termed as “muscid flies”. These include the
genera Musca (housefly), Hydrotaea (sweat fly),
Stomoxys (stable fly) and Haematobia (buffalo
fly).
Musca domestica or the common housefly has a
cosmopolitan distribution and serves as an
important carrier of different infectious agents.
The common housefly also serves as an
intermediate host to a wide variety of helminth
parasites.
Examine your specimen. Note that the thorax is
yellowish gray to dark gray bearing dark
longitudinal stripes which are equally wide and
extend to the posterior border of the scutum.
How many stripes are there? Note that a dark,
median longitudinal stripe is also present on the
yellowish ground colored abdomen, which later
becomes diffused on the 4th
segment in the male.
In the female, a band is present on either side of
the median stripe.
Study the head and its corresponding structures.
Note that the arista is present on the third
segment of the antenna. Note also that the arista
is bilaterally plumose all the way to the tip.
The mouthparts are highly modified and
specialized for imbibing liquid food in such a
way that only food particles that are about 4 um
in diameter can be ingested. Liquefiable solid
food, such as sugar, may be made fluid and
sucked up by ejection of saliva and crop fluids,
called vomit drop, which points important
disease transmission of houseflies.
Note that the labium is expanded distally into
two lobes of labella. The labrum is short and
spade-like, deeply grooved to accommodate the
hypopharynx. Is the mandible present? Note the
presence of a short maxillary palpi.
Examine the hairy legs. Identify the empodium
and pulvillus between the claws.
Study the wing venation. Note that the median
wing vein (M1+2) starts parallel to the radial
vein (R4+5) and afterwards in its course, curves
towards the latter, such that the first posterior or
apical cell (R5) is closed or nearly so. Note also
the presence of squama, antisquama and the
alula, arranged from proximal to distal.
Stomoxys calcitrans or stable flies are about the
same size as that of Musca domestica but its
abdomen is broader and shorter.
The proboscis of this fly is prominent and
directed horizontally forwards. It is bulbous at
the base narrowing distally. Note that the labium
terminates into two labella provided with cutting
structures called denticles or prestomal teeth.
The dorsal grove of the labium accommodates
the sharp labrum-epipharynx and hypopharynx.
The mandible and maxillae are absent. Only the
slender and short maxillary palpi are present
beside the proboscis.
Note that the arista is also present and plumose
but only on the dorsal side. The thorax is gray
and has four longitudinal stripes of which the
lateral pair is narrow and do not reach the

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scutum. The 2nd
and 3rd
abdominal segments are
provided with three prominent dark spots.
Examine the wing venation. Observe the course
of the median wing vein (M1+2) in relation to
the radial vein (R4+5). The former curves along
smoothly so that no angle is formed and the first
posterior or apical cell (R5) is open.
Identify the morphological characteristics. Label
the parts.
Haematobia has three important species in
veterinary medicine: H. stimulans, H. irritans
(hornfly) and H. exigua (buffalo fly).
They are the smallest biting muscid measuring 4
mm in length. The face and thorax is silvery
gray medially and dark laterally with well
defined dark stripes. The wing venation is
similar to that of the stable fly. The maxillary
palpi are stout and as long as the proboscis.
Which among the following is Stomoxys?
Haematobia?

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Exercise 6.
Obligate Myiasis Flies
Some dipterous insects whose larvae or maggots
invade tissues or organs of man and animals
cause a condition called “myiasis”. Adults are
capable of depositing their ova or larva on
wounds and around body openings, but they are
non-blood suckers.
Myiasis flies are classified into three groups
according to the oviposition or larviposition
habits of the fly: specific or obligate, facultative
or accidental.
Obligatory – must have a living host to complete
their development and are unable to survive in
the absence of the host
Facultative
Primary: adapt on ectoparasitic habit and are
capable of initiating myiases, may occasionally
live as saprophages in decaying matter
Secondary: normally live as saprophages and
usually cannot initiate a myiasis but may
secondarily invade pre-existing infestations
Accidental – rare or chance agents of myiasis,
which may invade an inappropriate host or
which may cause a myiasis when fly eggs are
ingested
Myiasis flies may also be classified based on the
organ affected:cutaneous, ocular, aural,
intestinal, gastric, nasal, rectal, scrotal, vaginal,
etc.
In this exercise,the focus will be on the
members identified under the obligate myiasis
flies.
Family Oestridae
Oestrus ovis
Mature larvae in the nasal passages are about 3
cm long, white, becoming slightly yellow or
brown as they mature, with dark transverse
bands on each segment. The ventral surface of
each segment bears a row of small spines. The
oral hooks are dark and prominent.
Adults are grey flies, about 10-12 mm in length
with small black spots on the abdomen and a
covering of short brown hairs. The head is
broad, with small eyes and the frons, scutellum
and dorsal thorax bear small wart like
protuberances. The segments of the antennae are
small and the arista bare. The mouthparts are
reduced to small knobs.
Gasterophilus spp.
The adult flies are large (11-15 mm). The body
is densely covered with yellowish hairs. The
thorax appears to have a dark transverse band on
it due to the black hairs present in the
mesonotum. Females ovipositor is strong and
protuberant. The wings characteristically have
no cross veins.
The third stage larva has a head that is tapering
anteriorly. The mouth is guarded with oral
hooks, dark hook-like processes. Take note of
the two rows of blunt-tipped spines located
dorsally and ventrally.
To distinguish the third larval stages of the
different species, see attached guide.

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Hypoderma spp.
Hypoderma linetaum
Hypoderma bovis
Adult female Hypoderma bovis are about 15 mm
in length whereas H. lineatum are about 13 mm.
They are bee-like in appearance covered with
dense hair in a characteristic light-dark color
pattern. The mouthparts of both species are
small and lack palps.
The third stage larva is initially whitish, and then
turns yellowish to light brownish as it matures.
The oral hooks are absent. However,note the
presence of flat tubercles and small spines on all
segments which make the segment prominent
from each other. The tubercles are absent on the
last segment of H. lineatum and the last two
segments in H. bovis.
H. bovis may also be distinguished from H.
lineatumby the observation of the posterior
spiracular plate. In H. bovis , the spiracular plate
surrounding the button has a narrow funnel like
channel whereas in H. lineatum,it has a broad
channel .
Dermatobia hominis
Adults are large, blue-black flies, with a yellow
orange head and legs. The thorax of the adults
possesses a sparse covering of short setae. The
aristae of the antennae have setae on the outer
side only.
The larvae of Dermatobia hominis have a
distinctive shape, being narrowed at the
posterior end, which become oval as they
mature. They have prominent, flower-like
anterior spiracles. The body segments are
covered with spines.
Family Calliphoridae
Cochliomyia
C. homnivorax
C. macellaria
They are green to violet green blowflies with
prominent black, longitudinal stripes on the
thorax and short palps.
Chrysomya
The adults have greenish to bluish body. They
have narrow dark bands along the posterior
margins of the abdominal segment and two faint
dark stripes on the thorax. The legs are dark, the
thoracic squamae are waxy white and the
anterior spiracle is black brown or dark orange.
They have a pale colored face.
The third stage larva is 18 mm in length. The
segments contain a belt of strongly developed
spines.

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Name and label the parts:

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Exercise 7.
Accidental and Facultative Myiasis Flies
Accidental myiasis flies are those whose ova or larva are deposited in manure or decaying
organic matter, garbage, carcass and myiasis is acquired by ingestion of ova or larva with contaminated
food or water. These become deposited around the anus or vulva and the larva upon hatching migrate to
the rectum, intestine or vagina. Flies are classified as accidental myiasis flies may also directly, but less
frequently, deposit the ova or larva into diseased tissues and neglected wounds, this becomes semi-
obligate myiasis flies.
Family Calliphoridae is composed of flies whose larvae are saprophagous, flesh feeders or
parasites of other arthropods. They are characterized by the presence of the hypopleural bristles on the
hypopleuron, which are placed like a screen on either side, in front of the metathoracic spiracles. They are
commonly called blowflies or bottle flies with their characteristic metallic blue or green color.
Lucilia contains two important blowflies: L. cuprina and L. sericata, causing blowfly strike of
sheep in Australia and Great Britain, respectively. They have bright metallic colors, bright green or
bronze color. They are specifically called “sheep blowfly” or “green bottle fly” or “copper bottle fly”.
Note that the eyes are typically brownish red. The abdomen is rounded posteriorly. Examine the arista and
mouthparts. Examine the wing venation. What does it resemble? Examine the squama. Take note that it is
covered with short hairs (microchaeta).
Calliphora are often called “blue bottle fly”, with bodies having a metallic blue sheen. The eyes
are red. Examine the squama. Note that aside from the microchaeta, long hairs are also present on it.
Family Sarcophagidae or flesh flies are large, medium sized to large and thick-set flies with light
or dark gray colors. Note that the arista is plumose to about its middle and bare in the distal portion. The
thorax bears three longitudinal stripes and the dorsum of the abdomen has dark spots or checkered black
gray (tosselated). The entire body is covered with bristly hair. The male terminal genitalia, hypopygium,
is prominent and bright red in color, while this feature is not present in females. These are larviparous
which deposit the larva in wounds or sores where the larva develop.
Examine the mouthparts and wing venation. What does it resemble?

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Exercise 8.
Posterior Stigmal Plates of Myiasis Larva
The larva of myiasis causing flies are generally
found on the host. Aside from the side of ovi or
larviposition, the bionomics of the larva and
some morphological features observed, the
primary measure of identification is based on the
structure and appearance of the posterior stigma
plates of third stage larvae.
The posterior spiracle is usually consists of a
pair of sclerotized spiracular plates. These may
be set flat on the body cuticle, raised on a
process or at the bottom of a deep body cavity.
Slits or openings are present on the spiracular
plate for gaseous exchange. In first stage larva,
the slits consist of a pair of simple holes. In
second and third stage larvae, each of the
sclerotized plates contains two or three slits,
respectively. The exception to this pattern are
the member of the subfamily Oestrinae, where
instead of slits, the posterior spiracles occur as a
large number of small pores. The outer rim of
the spiracular plate may be heavily sclerotized
and is known as the peritreme, which may form
a complete or an incomplete ring. In second and
third stage larvae, a rounded structure, known as
the button, may be visible on the sclerotized
plate in a ventral and lateral position. This
structure is the scar left from the spiracle of the
previous stage after moulting.
Examine the stigma plates of the third stage
larvae of some myiasis causing flies and note for
the following:
 shape and distance between stigma
plates
 shape, number and orientation of the
spiracular slits
 degree of sclerotization and
completeness of peritreme ring
 characteristic of buttons
Sarcophaga sp. Calliphora sp.

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NDENCARNACION 17
Lucilia sericata
Chrysomya bezziana
Cochliomyia homnivorax
Dermatobia hominis
Hypoderma bovis

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NDENCARNACION 18
Hypoderma lineatum
Oestrus ovis
Gasterophilus sp.
Musca domestica
Stomoxys calcitrans

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NDENCARNACION 19
Exercise 9.
Keds and Bugs
Keds or louse flies are pupiparous
dipterous insects, related to muscid flies. They
are markedly adapted to parasitic life, living on
blood of mammals and birds. The body is broad
and flattened dorsoventrally, the abdomen is
indistinctly segmented and usually soft-walled
and leather like. The wings may be present or
absent. The antenna has one joint and lies in a
pit on the forehead. The feet are provided with
strong claws, by which the parasite clings to the
hair or feathers of the host.
Forest flies under the Family
Hippoboscidae attack horse and cattle.
Hippobosca equina is more specifically called
“horse ked” or “horse louse fly”. These are flies
about 1 cm long with reddish brown color and
pale yellow spots. There is short and thick palpi
at the tip of the slender proboscis, with its main
portion withdrawn into the head at rest. The
veins of the wings are concentrated at the
anterior border. The larva is subglobular in
shape, measuring about 5x4 mm possessing a
dark spot at the posterior pole.
Sheep ked, Melophagus ovinus, is a
wingless, hairy, leathery insect, about 4-6 mm
long. The head is short, broad and not freely
movable. The thorax is brown and the abdomen
is grayish brown. Take note also that the legs are
strong and armed with stout claws. It is an
important intermediate host of a protozoan blood
parasite, Trypanosoma melophagium.
Melophagus ovinus
Lipoptena cervi is found in deer. They
originally have wings, but shed these after
finding a suitable host. They also have a leathery
body and has a brownish color. The head has a
sunken appearance into the thorax. The species
is L. caprina in goats.
Pseudolynchia canariensis (P. maura)
or the pigeon louse fly is an important
intermediate host of the Haemoproteus
columbae causing pigeon malaria. Study the
louse and note that the body is broad and
dorsoventrally flat, dark-brown in color.
Examine the antenna. How many joints are
there? Examine the palps. The abdomen is
leather-like and the wings are well developed.
Similar to H. equine, take note that venation is
reduced and concentrated along the anterior
border of the wings. Examine the claw. These
are strong and spurred.

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NDENCARNACION 20
Bugs are blood suckers, belonging to the
order Hemiptera. They are dorsoventrally
flattened with the proboscis jointed and flexed in
the head when not in use. Wings may or may not
be present.
The commonest member of order
Hemiptera is the bedbug. There are two
common species of bedbugs: Cimex lectularius
(common bedbug) and C. hemipterus (oriental
bedbug).
Examine the whole mount. Take note
that the body is elongate in shape and yellowish
brown in color. The female is slightly larger,
broader and more rounded than the male. Note
also that the entire body is covered with hairs
and bristles.
Examine the antenna. How many
segments are there? Examine the appearance of
each segment.
Locate the compound eyes. These
project conspicuously at the sides of the head.
Note if the ocelli is present.
Study the mouthparts. It is flexed
backwards, ventrally beneath the head when not
in use. The mouthparts consist of a small flap-
like, triangular labrum, stylet-like mandibles and
maxilla. The labium encloses the mandibles.
How many segments are there? Are the palps
and hypopharynx present?
Examine the large prothorax which
provides the head a sunken appearance. Note the
shape. This is a basis for identification of
species. Note that the lateral expansions are
more prominent in C. lectularius than C.
hemipterus. The mesothorax is small, triangular
and bear a pair of vestigial wings; hemelytra,
which partially covers the metathorax. The adult
has a pair of ventral thoracic stink glands, while
young stages have similar dorsal abdominal
glands.
Note the legs each terminating in pair of
simple claws.
Examine the abdomen. How many
visible segments are there? Examine the 8th
segment. In the male a notch can be found on its
left side, accommodating the saber-like penis or
aedeagus. In the female, a genital orifice is
found on the eight segment. While a copulatory
orifice is apparent on the fifth abdominal
segment, which leads to a blind pouch consisting
of an outer Organ of Ribaga and an inner Organ
of Berlese.
Kissing bugs or assassin bugs or cone-
nosed bugs, belong to the family Reduviidae.
The commonest species are Triatoma
sanguisuga (Mexican bedbug), T. proctata
(China bedbug) and T. rubrofasciata. These
bugs serve as important intermediate host of
Trypanosoma cruzi, causing Chagas disease in
man and T. canorini in monkeys and rodents.
Take note of the feeding habit of this bug, as
implied by its common name. These should be
differentiated from the plant pest members of
Family Reduviidae.
Examine a dried specimen. Note its
body is dark brown with red and yellow
markings on the thorax, abdomen and wings.
Note that its body is narrow and flat.
The head is narrow and elongate. In front is a
pair of compound eyes. Note that neck is not
obvious. The thorax is constricted anterior to the
middle and the functional wings are present on
the prothorax.
Examine the ocelli. Note that the
antenna bears 4 segments attached to the sides of
the anterior prolongation of the head. Note that
the proboscis resembles that of Cimex.

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NDENCARNACION 21
Exercise 10.
Fleas
Fleas belong to the Order Siphonaptera
(previously Aphaniptera) composed of two
families: Tungidae and Pulicidae. They are
wingless insects whose body is laterally
compressed about 1.5-4 mm long. The chitinous
covering is thick and dark brown in color.
Compound eyes are absent, however other
species have large simple eyes.
Examine the mountes specimen of the flea.
Examine the head and locate the short and stout
antenna sunk into the grooves on the side of the
head. Examine the genal comb or ctenidium, a
row of eight to nine spines on the cheek or gena
and the pronotal comb or ctenidium, located on
the posterior border of the pronotum. Take note
of the length and arrangement of the combs.
(This is significant for species identification).
The thorax is composed of three segments,
prothorax, mesothorax and metathorax. Each
segment bears a pair of legs.
Observe the legs. Note the powerful hindlegs
adapted for leaping. Locate the tibial notches
bearing spines.
Note that the abdomen is composed of ten
segments. Examine the ninth abdominal
segment. Note that the dorsal aspect bears a pin
cushion like plate called sensilium or pygidium
covered with sensory setae and pits. Note also
that the 8th
segment bears prominent antisensilial
setae.
Examine the ventral aspect of the ninth segment.
In the male, this is modified to form the claspers.
Also in the male, behind the sensilium, is a pair
of anal stylets, bearing apical setae and a number
of shorter bristles. Note that the penis or
aedeagus is chitinous and coiled. Observe for the
spermatheca in the female.
Ctenocephalidesfelis felis (cat flea)
The most common species of fleas affecting
dogs and cats. This flea serves as the
intermediate host of Dipylidium caninum, the
common tapeworm of dogs and cats in the
Philippines.
Ctenocephalidescanis (dog flea)
This species is less common that C. felis felis.
This flea is more restricted to dogs.
Study the prepared slides and note the following
differences between C. felis felis and C. canis:
• Genal comb (comparative length of the
1st
and 2nd
genal comb spines )
• Shape of the head
• Head dimension
• Number of tibial notch bearing setae and
arrangement of the setae
Assignment:
Picture or illustration of the following fleas, and
take note of their distinct characteristics:
Echidnophaga gallinacea (stick tight flea)
Pulex irritans (human flea)
Tunga penetrans (sand flea)
Xenopsylla cheopis (orientalrat flea)

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NDENCARNACION 22
Exercise 11
Sucking Lice of Mammals
General Characteristics
1. Lice are classified under the order
Phthiraptera and further subdivided as
either chewing lice or sucking lice.
2. They are wingless insects living as
obligate, permanent ectoparasites of
mammals.
3. Sucking lice are classified under the
suborder Anoplura.
4. Their mouthparts are adapted for
sucking tissue fluids and blood from the
host. The mouth consists of a three
piercing stylets: dorsal medial and
ventral, located in a pouch within the
head, protrusible through a small snout-
like tube known as the stoma. This is
everted during feeding, anchoring the
louse to the hosts skin by means of the
prestomal teeth on its inner wall.
Mandibles are absent.
5. The two antennae are visible at the sides
of the head and are usually composed of
five segments.
6. The female has two pairs of lateral
gonopods that arise from the ventral
aspect of abdomen giving the abdomen
a blunt ended shape
7. Male has a pointed/rounded posterior tip
due to the sclerotized genitalia known as
pseudopenis
8. The thorax is small and the segments are
fused together.
9. The abdomen is relatively large, with 7-
9 visible segments.
10. The families of veterinary importance
are: Haematopinidae, Linognathidae,
Pediculidae, Haplopleuridae and
Echinophthiriidae
Family Haematopinidae (short-nosed louse)
1. These are the largest species of lice
2. Eyes are absent.
3. Head is sharp and has a prominent
forward prolongations, temporal angles,
behind the antenna
4. The thorax is broad, with three pairs of
legs attached. Note that the legs are of
equal sizes with tarsus bearing strong,
curved claw which grip the hair of the
host with the tibial spur, a thumb-like
process on the ventral and distal angle of
the tibia. In addition, a tibial pad
(prevent slipping) may be present
between them.
5. Segments 2 or 3 to 8 of the abdomen
bears dark brown or black areas of
thickened chitin at the sides called
paratergal plates. The segments also
bear, one row of spines.
Haematopinus suis (pig louse)
 Only species of louse that occur in pigs.
 Largest known species of sucking lice
(4-6 mm).
 Grayish brown in color with black
markings
 Note that its head is two to three times
as long as it is wide.
 The paratergal plates are lobe-like.
Haematopinus asini (horse sucking louse)
 Occur in equines.
 3-3.5 mm
 Resembles H. suis but its paratergal
plates are small and tuberculate.
Haematopinus eurysternus (short-nosed cattle
louse)

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 Short-nosed cattle louse
 Average 2.5 mm in length
 Can be distinguished by its short,
pointed head and broad body
 Head and thorax are yellow brown
 Abdomen is blue gray
 The paratergal plates are tuberculate but
larger than H. asini
 Has 2-3 setae behind each paratergal
plate
Haematopinus tuberculatus (buffalo louse)
 Affects water buffaloes.
 Resembles H. eurysternus except it has
more setae behind each paratergalplate
Haematopinus quadripertusus (taillouse)
 Affects cattle in tropical regions.
Family Linognathidae (long-nosed louse)
1. These are the smallest species of
sucking lice.
2. Most of the members are parasitic to
primates (human and non-human).
3. Eyes are absent.
4. Abdomen is membranous with
numerous rows of hairs on its segments.
5. Paratergalplates are absent.
6. The first pair of leg is usually smaller
while the third pair is the largest
7. There are 2 genera of interest under this
family: Linognathusand Solenoptes
Linognathusvituli
 Long nose cattle louse
 Reported in the Philippines
 The head is apically acute.
 Pre-antennalregion is elongate
 The lateral margins of the post antennal
region are straight and parallel.
Linognathusovillus
 Blue louse of sheep, face louse
 Head is much longer than wide and
longer than the thorax
Linognathusafricanus
 African blue louse
 Occurs in sheep and goat
 Most common sucking lice of goats in
the Philippines
 Note the strongly convex lateral margins
of the post antennal regions
Linognathusstenopsis
 Affects goats
 Resembles L. africanus except that the
lateral margins of the post-antennal
region is not strongly convex (slightly
convex).
Linognathussetosus
 Occur in dogs and foxes.
 The pre-antennal region is broader than
long and apically blunt.
 The lateral margins of the post-antennal
region are only straight and parallel
Solenoptes capillatus
 Capillate cattle louse
 The abdominal spiracles are set on
slightly sclerotized tubercles.
Family Pediculidae
1. Members of this family are parasitic to
man and primates.

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NDENCARNACION 24
2. Pigmented eyes are present
3. Abdominal segments bear paratergal
plates
Pediculus humanus capitis – human head louse
Pediculus humanus corporis – human body
louse
 Note that the legs are of equal size and
the claws are slender
Phthirus pubis – pubic louse or crab louse
 Note the shape of the body, broad and
short
 The legs are long with stout claws
 The paratergal plates are prominently
tuberculated
Other species:
Pedicinus eurygaster – Asian macaques
P. obtusus – leaf monkeys, green monkeys and
babboons
P. patas – colobus monkey
P. mjobergi – howler monkey
Family Halopleuridae
1. Largest family of sucking lice, primarily
affecting rodents.
2. The paratergal project apically from the
body
3. Tergal and sternal plates are distinct.
Polyplax serrata and P. spinulosa
 Common lice of laboratory mice and rat,
respectively.
 Slender, yellowish-brown in color
 Well formed lateral plates on the dorsal
and ventral aspect of the
abdomen.
Family Echinophthiridae
1. Lice of pinniped carnivores.
2. Bodies are densely covered with thick
setae sometimes modified into scales.
3. Two genera:Antarctophthirus and
Echinophthirus.

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NDENCARNACION 25
Exercise 12
Chewing Lice of Mammals
Chewing lice are classified under Order
Mallophaga. These are small obligate
ectoparasites of mammals and birds. The
antenna is short composed of three to five
segements and may not be visible. The eyes are
vestigial and the segmentation of the thorax is
not distinct. The head is broader than the thorax.
The mesothorax and the metathorax are fused.
The tarsus bears one claw. Maxillary palps may
be present or absent.
The suborders of veterinary importance are
Ischnocera and Amblycera.
Suborder Ischnocera
The antenna is filiform and visible at the sides of
the head and composed of three to five
segments. The head resembles that of sucking
lice however these are broader compared to
sucking lice. There are no maxillary palps. The
mandibles bite vertically. The first and second as
well as the ninth and tenth abdominal segments
are fused and the 11th
segment may not be
visible.
Damalinia equi - affects equines. The head is
rounded in front, the antenna inserted well so
that the head forms a perfect semi circle in front
of the base of the antenna.
D. ovis – found in sheep. The head is rounded in
front similar to D. equi but the post antennal
region is narrower than the pre-antennal region.
D. bovis – found in cattle. The preantennal
region of the head is relatively pointed while the
post-antennal region is rounded.
D. limbata – found in goats. The most common
chewing lice of goats in the Philippines. The
anterior margin of the head is flattened or
slightly concave. The preantennal angles are
expanded and relatively pointed.
Felicola subrostrata – affects cats. The lateral
margin of the pre-antennal region is straight,
converging anteriorly to a strong apex with
distinct narrow emargination
Trichodectes canis – occur in dogs. The pre-
antennal region is flattened and the post antennal
region is rounded.
Suborder Amblycera
The antenna is clubbed and almost entirely
concealed in the grooves on the underside of the
head. Maxillary palps may be present.
Heterodoxus spiniger - dogs. This serves as the
IH of Dipylidium caninum. The head is more or
less triangular in shape. Two long posteriorly
directed spines are located behind the mandibles.
Heterodoxus longitarsus and H. macropus –
kangaroos and wallabies
Gyropus ovalis, Gliricola porcelli and
Trimenopon hispidum – found in guinea pigs
and the former two are from rodents.

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NDENCARNACION 26
Exercise 13
Lice of Poultry
Members of the Order Mallophaga are the only
lice affecting poultry. These lice can be
distinguished from those found in mammals by
the presence of two lateral claws.
Suborder Ischnocera
Goniocotes gallinae/ hologaster (Goniodes
hologaster) – fluff louse.
 Note the size and shape of the body.
 Examine the head and note the angulate
temporal lobes, parallel margins of the
post-antennal region, bearing two long
setae on each margin.
Goniodesdissimilis – brown louse.
 Note the size of the brown louse
compared to the fluff louse. It is larger.
 Examine the head and note that the
temporal angles are also angulated
however the lateral margins of the post-
antennal region is not parallel.
 These margins bear two long setae and
in addition, each angular process bear a
short spine.
Lipeureus caponis – slender wing louse
 Note the shape of the body
 Note that the head is elongate and
rounded in front
 Temporal lobes are absent
Oxylipeurus polytrapezius
 Resembles L. caponis,except that the
anterior margin of the head bears a
series of backward projecting chitinized
process
Chelopistesmileagridis – common louse of
turkey
 Note the size and shape of the body
 Examine the head and note the
angulated temporal lobes which extend
far backwards,terminating in long stylet
like processes.
Columbicola columbae – pigeon louse
 Study the head and note its elongate
shape
 The lateral margins of the preantennal
region are straight and slightly tapering.
 Temporal lobes are rounded.
 At the anterior end are two pairs of
spines, one pair pointed backwards,the
other forwards.
Anaticola crassicornis and A. anseris – duck
louse
Suborder Amblycera
Menopon gallinae – shaft louse
 Note the size and shape of body.
 Examine the head, it has rounded, blunt,
preantennal region with a wide post
antennal region.
 How many setae are there in each
abdominal segment?
Menacanthus stramineus – yellow body louse of
chicken
 Note the size of the body and the shape
of the head.
 Note also that each abdominal segment
bears two rows of bristle.
Menacanthus pallidulus
 Examine the head. Locate the two short,
spine like processes behind the
mandibles
 Examine each abdominal segment and
note the number of rows of setae.

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NDENCARNACION 27
Exercise 14
Ticks
Ticks are classified under the Order Arachnida,
together with mites, spiders and scorpions.
Arachnids differ from insects primarily in
structure and function. The antenna, wings and
compound eyes are absent, same as the well
defined division of the body into head, thorax
and abdomen. The mouthparts are developed
primarily to feed on tissue fluids which they
suck up by means of a sucking pharynx.
Examine the mouthparts. It is composed of a
pair of chelicerae (cutting structure bearing teeth
with movable terminal digits), a pair of
pedipalps (4-segmented structure) and between
them is the median toothed structure called
hypostome. These mouthparts are attached to a
plate called basis capitulum and borne on the
gnathosoma. The basal joint between the
pedipalps and the gnathosoma may bear teeth to
help them in chewing prey. These teeth are
known as gnathobases.
Study the body of a tick. Note that it is not
clearly divided into the regions as head, thorax
and abdomen. The body of the thick is just
divided into the anterior gnathosoma (composed
of mouthparts and the basis capitulum) and a
posterior single piece which represents the fused
podosoma and opisthosoma, termed the
idiosoma. The podosoma is further characterized
as propodosoma and metapodosoma.
Ticks of veterinary imlportance are divided into
two families: Argasidae and Ixodidae,or soft and
hard ticks, respectively.
Family Argasidae
The integument is leathery and frequently
mammillated. The capitulum and mouthparts are
situated anteriorly on the ventral surface and not
visible on the dorsal aspect. Eyes are absent or
there may be two present on the supracoxal
folds. Note that a pair of spiracles is situated
postero-laterally to the third coxae. Sexual
dimorphism is not marked.
Argas persicus
“fowl tick”. This has not been reported in the
Philippines. It transmits Aegyptianella pullorum.
Note that the body is oval, narrower anteriorly
than posteriorly, and dorsoventrally flattened.
Several buttons and discs are present on the
dorsum. Examine the periphery of the body and
take note that it is distinctly flattened and lined
with quadrangular plates.
A starved tick is yellowish brown in color with a
dark intestine showing through the tegument. An
engorged one has slaty-blue color.
Argas reflexus – pigeon tick
Otobius megnini
“spinose ear tick”. Only the larva and the nymph
stages are parasitic on the ears of dogs, sheep,
horse, cattle and sometimes, goats, pigs, cats,
ostriches and man.
An engorged larva is almost spherical in shape.
The nymphs have bodies widest at the middle
and their tegument bears spine like processes.
The color is bluish gray and legs and mouthparts
are pale yellow. The non-parasitic adult, have a
constriction in the middle of the body.
Ornithodoros maubata

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NDENCARNACION 28
“eyeless tampan of Africa”. Attack man,
domestic and wild animals and birds. This tick is
responsible for transmitting African Swine
Fever, Coxiella burnetti, Borelia anserine, and
Aegyptianella pullorum.
Family Ixodidae
Ticks of this family possess the scutum, a hard,
chitinous shield which extends over gthe whole
dorsal surface of the male and cover a small
portion in the larva, nymph and female. The
mouthparts are located anterior and visible from
the dorsal aspect. A pair of spiracles is situated
postero-laterally on the fourth coxae.
The scutum has bilateral cervical and lateral
grooves, varying in depth and length in species.
The body of the female may have a pair of
lateral “marginal grooves” behind the scutum,
and postero-lateral and median grooves are
present in both sexes. The posterior border of the
body may be notched, forming several, usually
11, rectangular plates called festoons. Males
have ventral plates.
Examine the legs. Note that each leg consists of
the coxa, trochanter,femur, genu, tibia, tarsus
and claw and pulvillus. Located on the tarsi of
the first pair of legs is a pit known as Haller’s
organ,packed with chemoreceptor setae,used in
host location. The coxae are armed bearing an
internal spur.
Locate the genital orifice situated in the midline
on the anterior half or third of the ventral surface
of the tick and the anus near the posterior end.
Ixodes ricinus
“castor bean tick”. Adults are found in domestic
and wild animals while the nymph and larvae
have been found in lizards and birds. These ticks
are responsible for transmitting Babesia
divergens, B. bovis,Anaplasma marginale,
Coxiella burnetti and Louping ill virus.
Examine the body. Note that the anal grooves
are located anterior to the anus. The palpi are
long. The eyes and festoons are absent. The
ventral surface of the male is armed with
pregenital, medial, anal, epimeral and adanal
shields. The stigmatic plates are oval in the male
and circular in the females.
Rhipicephalus spp.
R. appendiculatus – brown ear tick
R. sanguineus – brown dog tick
R. evertsi – red legged tick
They are usually inornate. Eyes and festoons are
present. The hypostome and the palpi are short.
Basis capituli hexagonal dorsally. The first
coxae bear two strong spurs. Males with adanal
and accessory shields. Spiracular plate is
comma-shaped in females and long in males.
Boophilus spp.
B. annulatus – North American cattle tick
B. microplus – tropical cattle tick
Take note that males are smaller than females.
Examine the body and take note that the anal
groove is absent in the female, faint in males and
it surrounds the anus posteriorly. Eyes are
present and the festoons are absent. Palps and
hypostome are short. Spiracles are circular or
oval. Examine the posterior end of the male, it is
provided with anal or accessory shields and a
caudal process.

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NDENCARNACION 29
Exercise 15
Mites of Mammals
Mites affecting mammals generally come from
three suborders under Order Acarina, namely
SO Astigmata, SO Prostigmata and SO
Prostigmata.
Suborder Astigmata
 Also called Sarcoptiformes. Parasitic
mites which cause sarcoptic mange in
mammalsandscabiesinman.
 These miteslackstigmataor spiracles
 The first and second coxae are widely
separatedfromthe 3rd
and4th
 The ventrum of the mite is devoid of
conspicuous shields and tarsi are
equipped with suckers called
sarcoptiformpretarsi
FamilySarcoptidae
 Mange mites
 Cause mange, dermatitis characterized
by pruritus, alopecia and epidermal
hyperplasia with desquamation.
Rubbing and scratching leads to deeper
wounds which is typically complicated
withsecondarybacterial infection
Sarcoptesscabiei– causesscabiesinman
S. scabiei varequi - horses
S. scabiei varbovis – cattle
S. scabiei varovis – sheep
S. scabiei varcaprae– goat
S. scabiei varsuis – pig
S. scabiei varcanis – dog
S. scabiei varcuniculi – rabbit
 The body isroundedtooval
 Dorsal surface with transverse ridges,
strong setae and central patch of
triangularscales
 Mouthparts have a rounded
appearance
 Legs are short and stumpy, in which the
3rd
and 4th
legs do not project beyond
the posteriormarginof the body
 Anusisterminallylocated
 The pretarsi of legs 1 and 2 in female
and 1,2, 4 in males terminally bear bell-
shaped tarsal sucker or caruncle, set on
longslenderunjointedstalkorpedicel
Notoedrescati
 Parasitic to cats and rabbits, chiefly on
ears andback of the neck
 Mouthpart issquare.
 Dorsal striations tend to be in
concentricrings(thumb-printlike)
 Simple dorsal setae
 The anus of Notoedres is located
dorsally
 Legs are morphologically similar to
Sarcoptes
FamilyPsoroptidae
 Scab mites
 Unlike Sarcoptes they do not burrow
the skin causing thick, heavy scabs
rather thanhyperplasia
Psoroptes spp.

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P. equi– horse
P. bovis – cattle
P. caprae– goat
P. cuniculi – rabbit
 Morphologicallysimilarto Sarcoptes
 Body is oval in shape, dorsal spines are
absent
 All the legs are long and projecting
beyondthe marginof the body
 In males the third leg is longer than the
fourth
 Anusisterminallylocated
 Caruncles are set on long 3-segmented
pedicles of legs 1,2 and 4 in females and
1,2 and 3 in males
 Whip like setae is present on the third
and fourth leg of the females and
males,consecutively.
 The posterior margin of the male bears
two lobes called copulatory tubercles
each bearingadanal suckersatthe base
Chorioptes spp.
Chorioptes equi – causes chorioptic mange in
equinesandcattle
Chorioptesbovis – cattle
Chorioptesovis - sheep
Chorioptescaprae– goat
Chorioptescuniculi- rabbit
 Shorterunjointed pedicle
 female with suckers on legs 1-2-4, 3rd
have longsetae
 1st and 2nd
are strongerthanthe others
 male with suckers on legs 1-2-3-4, 4th
is
extremelyshort
Otodectescyanotis
• Similar in appearance to Chorioptes
(size,unjointedpedicel)
• Suckersare cup-shaped
• Female: Legs 1,2  sucker; Legs 3,4 
with terminal whip-like setae, 4th
leg is
reduced
• Male:All legshave sucker
Suborder Prostigmata
 alsoknownas Trombidiformes
 may or may not bear a stigmata near
the head
 stigmata attached to a trachea-like
structures calledperitreme
FamilyDemodicidae
Demodex canis - dog
Demodex equi– horse
Demodex bovis – cattle
Demodex ovis – sheep
Demodex caprae– goat
Demodex phylloides – pig
Demodex folliculorum – man
 Specialized mites that inhabit the hair
folliclesand sebaceousglands
 Species are difficult to differentiate
because the only major difference is the
size,aside fromthe hostaffected
 Generally, has an elongated “cigar-
shaped” body, appears to be divided
intohead,thorax and abdomen.

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 The “thorax” bears the four short
stumpylegs.
 The abdomen is transversely striated
dorsallyandventrally.
 The penis of the male protrudes on the
dorsal side of the thorax
 Vulvaisventral inthe female
 Eggs are spindle shaped.
 Larva and nymph bear three pairs of
legs
FamilyCheyletiellidae
Cheyletiella parasitivorax –rabbitfur mite
 Alsoaffectsdogsandcats
 Alsocalledwalkingdandruff
 Identified bythe bigpalpal claws
 M-shapedgnathosomal peritreme
 Comblike tarsal appendages
FamilyPsorergatidae
Psorergatidaeovis – sheepitchmite
 Cause Austarlianitchinsheep
 Body is almost spherical, with sides
indented between each leg, which are
radially arranged each bearing a pair of
tarsal claws
 Femur of the legs bear long setae on
the ventral side and a large curved
spine directedinwards
 There isa single dorsal plate
 In the female, a pair of setae is located
on the posterior end arising from the
medianlobesof the female
FamilyTrombiculidae
 Chiggermite orharvestmite
 Usually scarlet, red, orange or yellow in
color
 Nymphs and adults are free living and
onlythe larvae are parasitic.
 The larva are six-legged, attacking wide
variety of wild and domestic animals
includingbirds
Suborder Mesostigmata
 These mites have the stigmata in the
middle portion of the body lying
between the third and fourth coxae on
each side of the body connected to a
sinousperitreme
 Coxae are evenly shaped, however
these are crowdedinto the anterior half
of the body
 Tarsus is generally armed with claws
and the ventrum is armored with
sclerotizedshields
Ornithonyssusbacoti– tropical rat mite
 Dorsal plate is narrower than the other
speciestaperingtoabluntpoint
 Numeroussetae coverthe body
 Chelicerae have no teeth, spur is
present on the distal segment of the
pedipalp
 Sternal plate bears three pairsof setae
 Anus located on the anterior half of the
anal plate
Ornithonyssus caninum – lives in the nasal
passagesandsinusesof dogs
Ornithonyssus simicola – parasitic in bronchi of
the rhesusmonkey

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Exercise 16
Mites of Poultry
Mitesaffectingpoultryalsocome fromthe
same subordersof the mitesof mammals.
Suborder Astigmata
 Generallyare calledfeathermites
GenusCnemidocoptes
 Resembles Sarcoptes,withglobose
bodieswithinterruptedstriation
formingscales howeverthe spinesare
absent.
 Two longitudinal barsrunfromthe base
of the pedipalpstothe levelof the legs,
where theyare unitedbya transverse
band
 Legsand pediclesare shortandstumpy
 All legsof the male bearcaruncleswhile
femaleshave none.
Cnemidocoptes gallinae– deplumingitch
mite infowls
C. mutans –scaly legmite infowlsand
turkey
C. pilae – budgies
C. jamaicaensis –goldenthrush
C. fossar– Maja finch
Megniniacubitalis –attacks chicken.Reported
inthe Philippines.Foundbetweenthe barbules
of the feathers
 Bodyis roughlyoval
o In the female,the posterior
marginis more roundedwhile
inthe male itisbilobed,
presentingtwolongcopulatory
tuberclesbearingtwo
prominentcopulatorysuckers
at the base.
 All legsextendbeyondthe marginof
the bodyand bear suckerssetonshort
unjointedpedicles
o In the female,the anteriortwo
pairsare relativelystouterand
shorterthan the posteriorpairs
o In the males,the thirdpairof
legsisexceptionallydeveloped.
o In bothsexes,aclaw like
empodiumispresentonthe
pretarsusof the anteriortwo
pairsof legs.
M. velata – duck
M. phaisiani– pheasantandpeacock
M. columbae– pigeon
Pterolichusobtusus
 Parasiticonthe feathersandskinof
fowl.Presentinthe Philippines
 Bodyis roughlyoval
o Female –posteriorendis
broadlyrounded
o Male – taperingandbilobed
 All legsare equal indevelopmentand
bearlarge cup-shapedcarunclesinboth
sexes.
Cytonidesnudus
 Airsac mite of fowls.
 Bodyis verysmall,oval creamincolor
withcarunclesonall legs
 Hairless

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Suborder Mesostigmata
 Majorityof poultrymitesbelong
Dermanyssusgallinae– redmite of poultry
 Generallyattacksfowls,but
occasionallyhumans
 Normallycoloredwhitish,grayishor
blackhoweveritturnsredafter feeding
on hostsblood
 Dorsal shieldispresent,whichdonot
reach the posteriorendof the body.
o The posteriormarginis
truncated.
 Anusislocatedsubterminal onthe
posteriorhalf of the anal plate
 Chelicerae are longandwhiplike
Ornithonyssussylvarium
 Northernfowl mite
 Can be distinguishedfromothersdue to
the shape of the dorsal plate,whichis
widerthanlongon the posteriortwo-
thirdsand taperslaterforminga tongue
like anteriorend
 Anusislocatedon the anteriorhalf of
the anal plate
 All fourpairsof legsterminate inaclaw
like structure andbearssuckers
Ornithonyssusbursa
 Tropical fowl mite,hanip
 Can be distinguishedfrom O.sylvarium
by the shape of its dorsal plate,which
graduallytaperstoa bluntposterior
end.
 Anusislike O.sylvarium.

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Exercise 17
Amoeba (Sub-Phylum Sarcodina)
Sub – Kingdom protozoa include
unicellular organisms within which all functions
of life are performed. They form the most
primitive group in the Animal Kingdom.
The structures of protozoa are not
referred to as organs as in higher animals but as
organelles; organ being composed of cells and
organelles being differentiated portions of a cell.
The nucleus may be one of the two
types. In protozoa, other than ciliates, it is
vesicular containing a more or less central body
called the nucleolus or endosome.
The cytoplasm is divided into an outer
ectoplasm and an inner endoplasm. The
ectoplasm is bound by a delicate, non-rigid
membrane: the periplast.
Protozoa move by means of
pseudopodia, flagella or cilia.
Sub-Phylum Sarcodina is composed of
members, which do not possess a thick periplast
and move by means of pseudopodia, rarely
having flagella. With several exceptions,
reproduction is usually asexual by binary fission.
Nutrition is holozoic. Parasitic amoeba strictly
belongs to Family Endamoebidae which occurs
in the digestive tract of vertebrates and
invertebrates.
Entamoeba hystolytica
 It occurs in the large intestine of
primates and man, causing amoebic
dysentery.
 It also occurs in puppies and kittens.
 It occurs in 2 forms: trophozoite and
cyst.
 The trophozoite form is mobile, moving
by means of pseudopodia.
Examine a stained smear of intestinal contents
containing trophozoites. Locate an organism and
note that it is irregular in shape on account of
pseudopodia. The single spherical nucleus has a
distinct central endosome. The cytoplasm is
granular and contains erythrocytes, leukocytes
and tissue cell fragments in food vacuoles. This
characteristic serves to differentiate E.
histolytica from other non pathogenic species of
amoeba.
Examine a stained preparation of cyst and
observe for the following characteristics:
 The cyst is spherical to ovoid.
 The cyst wall is demonstrable only in
fresh preparations.
 Immature cysts have 1-3 nuclei while
mature cysts have 4.
 The nucleus resembles that of
trophozoite but is generally smaller.
 The cytoplasm contains deep staining
retractile rods (chromatoid bodies) and
diffused collagen vacuoles. These
structures disappear as cyst matures.
Entamoeba coli
This is a non-pathogenic form in
humans and its importance lies in the fact that it
must be distinguished from the pathogenic E.
histolytica. This commonly found in the cecum
and colon. Other hosts include monkeys, dogs
and pigs.

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Examine the preparation of E. coli trophozoite.
It can be distinguished from E. histolytica by the
contents of its food vacuoles (bacteria, yeast,
starch, grains and vegetable debris). Its nucleus
has a larger eccentric endosome with coarser
granular chromatin material. Newly formed cyst
is uninuclear but mature cyst has 8 nuclei.
E. gingivalis – common in the mouthespecially
at the base of the teeth with tartar.

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NDENCARNACION 36
Exercise 18
Hemoflagellates ( Subphylum
Mastigophora)
In Subphylum Mastigophora, in addition to the
nucleus,there is an associated structure,the
kinetoplast. It is located at some distance from
the nucleus and is composed of two parts:
(1) blepharoplast – a round or oval
granular structure at the base of the flagella.
(2) parabasalbody – a round or oval
rod-like structure close to the blepharoplast.
Flagella are fine, filamentous, whip like
structures. In some species, a flagellum may
pass backward along the body along its entire
length or at several points to form an
undulating membrane.
Members of the family Trypanosomatidae are
all parasites normally found in the blood and
tissues of mammals and birds. They evolved
from parasites of the alimentary canal of insects.
They are typically leaf-like in shape with a
single flagellum attached to the body in an
undulating membrane. There are four
developmental stages: trypomastigote,
epimastigote, promastigote, amastigote.
 Trypanosome (trypomastigote) stage;
leaf-like kinetopast post. to the nucleus
near the posterior end. Undulating
membrane present. Occurs in vertebrate
host but also in arthropods as infective
stage (Metacyclic trypanosome) for
vertebrate host.
 Critidial (epimastigote) stage – Leaf-
like; kinetoplast anterior and near the
nucleus. Short undulating membrane.
Occurs in arthropods and vertebrate
hosts.
 Leptomonad (promastigote) stage. Leaf-
like, kinetoplast near the anterior end.
No undulating membrane. Occurs in
arthropods and plants.
 Leishmania (amastigote) stage.
Rounded/ovoid kinetoplast present but
without free flagellum. Occurs in
vertebrate and arthropods. All stages
may occur in culture medium
The genus Trypanosoma generally occurs in
vertebrates and arthropods. There are four
developmental stages. Most species occur only
as trypomastigote in vertebrate host.
Trypanosoma evansi – The organism is
monomorphic and measures 25 microns in
length. It is extracellular in position.
Examine a stained blood smear from a infected
horse. Locate the organism under HPO.
Examine it more closely under oil immersion
noting the following features:
 Nucleus – oval and situated at
about the middle of the body
 Kinetoplast – well defined and
subterminal
 Undulating membrane – well
developed
 Flagellum – free and long

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Note also the staining characteristics of the
organism and its size relative to the red blood
cells.
Trypanosoma lewisi – cosmopolitan parasite of
rats. Transmitted by the rat flea Ceratophyllus
fasciatus. It is non-pathogenic, being important
only as it may be mistaken for T. evansi if an
infected rat is inoculated to diagnose surra.
Examine a stained blood smear from an infected
rat. Note the following characteristics:
 About the same size as T. evansi
 Body is slender with pointed ends.
 Nucleus is oval and lies anterior to the
middle of the body
 Kinetoplast is well developed and
located some distance from the posterior
end.
 The undulating membrane is
inconspicuous.
 Free flagellum is long.
 Developmental stages of Leishmania
occur in the amastigote form in
vertebrates and in the promastigote form
in the insect vector and in cultures. All
species are morphologically the same.
Leishmania donovani – cause “visceral
leishmaniasis”
Note the following:
 Round or oval
organism, occur in
clusters in the
cytoplasm.
 The nucleus is red and
oval
 The kinetoplast is red
and rod shaped.
 The cytoplasm is blue
but ordinarily, only the
nucleus and kinetoplast
are seen

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NDENCARNACION 38
Exercise 19
Order Polymastigida
Order Rhizomastigida
Members of Order Polymastigida
(Trichomonadida) bear four to six flagella,
one of which is trailing, frequently attached
to an undulating membrane. They bear 1 or
2 nuclei and reproduce asexually by binary
fission. Genera of veterinary importance are
Tritrichomonas, Giardia and Hexamita.
In Trichomonas sp.,and allied forms, a clear
rod like axostyle arises from the
blepharoplast and passes through the center
of the body to emerge with a sharp point at
the posterior end.
Trichomonasgallinae – occurs in the upper
digestive tract of pigeons. It may also affect
chickens and turkeys. It is pyriform in
shape. A single nucleus is situated in the
anterior part of the body. Anterior to the
nucleus is a blepharoplast arising from
which, are 4 anterior flagella and a posterior
recurrent flagellum running along an
undulating membrane. The posterior
flagellum does not extend to the tip and
there is no trailing flagellum. A rod-like
axostyle runs through the body from the
blepharoplast and emerges through the
posterior end.
Members of Family Hexamitidae are
pyriform bearing two nuclei. Six anterior
and two posterior flagella arise near the
anterior end and two axostyles. Some
members form cysts. Severalmembers are
free living in stagnant water while others are
parasitic to insect, fish and frogs.
Hexamita mileagridis – found principally in
the duodenum and small intestine of turkey,
however, it may also occur in quail,
pheasants,chicken, domestic ducks, etc. The
organism is bilaterally symmetrical and pear
shaped. The six anteriorly directed flagella
arise in two groups from each distinct
blepharoplast lying anterior to the nuclei.
The caudal flagella arise on each side from a
distinct blepharoplast posterior to the larger
anterior blepharoplast and pass posteriorly.
Giardia lamblia – occurs in the lumen of the
small intestine of man. It has also been
reported in pigs, rats and mice. It occurs in 2
forms: trophozoite and cyst. The trophozoite
form is bilaterally symmetrical and pyriform
in outline, with a broadly rounded anterior
and pointed posterior end. The dorsal
surface is convex and the ventral surface is
concave or flat with 2 large sucking discs on
the anterior half. There are 2 nuclei. Slender
median axostyles and 8 flagella in 4 pairs.
The cyst form is oval to elliptical in shape
and thin-walled. Two to four nuclei are
situated near the pole.
Order Rhizomastigida

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Histomonas are amoeboid with a single
nucleus. A single flagellum arises from the
basal granule, close to the nucleus.
Histomonas mileagridis – occurs in the ceca
and liver of turkeys, causing blackhead or
infectious enterohepatitis. It may also affect
chickens and quails. It is transmitted via the
eggs of the cecalworm, Heterakisgallinae.
The organism is pleomorphic, its
morphology depending on organ location. In
the cecallumen or in culture, it is flagellated
with 1-4 short, fine flagella arising from a
small blepharoplast. There is no undulating
membrane or axostyle. It tissue, it is
amoeboid and occurs singly or in clusters.
There is no flagellum.

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NDENCARNACION 40
Exercie 20
Coccidia (Genus Eimeria and
Isospora)
Coccidiaare typicallyintracellularoccurring
chieflyinvertebrates.The differentgenera
of the familyare differentiatedbythe
numberof sporesor sporocystsand
sporozoitesineachsporulatedoocyst.
Eimeria are commonlyfoundinepithelial
cellsof the intestines.Theyhave asingle
hostwhereintheyundergoasexual and
sexual multiplication.The macroand micro
gamontsdevelopindependently.The
zygote resultsfromthe unionof the
gametesandsporocystsare formedby
sporogony.
Eimeria tenella – occurs in the caeca of
chickens.Itisthe mostcommonand the
mostpathogeniccoccidianspeciesin
chickens,causingthe conditionknownas
caecal coccidiosis,characterizedby
hemorrhage anda cheesynecroticcore.
Cystsare formedwhichare passedinthe
fecesandsporulate onthe groundto
become infective.
Eimeria necatrix isnextto E. tenella in
pathogenecity.Itcausesdistensionor
ballooningof the middleintestine filled
withunclottedblood.Thismayaffecteven
olderbirds.
E. acervulina occurs in the duodenum,
characterize byinitial hemorrhagefollowed
by numerousgrayor whitishtransverse
patches.
E. maxima andE. brunetti causessloughing
of the intestinal mucosa.
Otherimportantcoccidianparasites
occurringin otherdomesticanimalsinclude
E. zuernii, the mostpathogeniccoccidian
parasite of cattle and waterbuffalo; E.
ashata,the mostpathogenicinsheepand
goats; E. debliecki, the mostcommon and
Isospora suis,inswine;and E.leuckarti and
Klossiella equi inhorses.
E. canis and I.canis are reportedindogs
while E.felina,E. cati, I. bigemina,I.rivolta
and I.felis incats.

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NDENCARNACION 41
Exercise 21
Coccidia (Genera Sarcocystis and
Toxoplasma)
For Sarcocystis a two hostlife cycle has
beenestablishedwithcarnivoresas
definitivehostandherbivoreslike swine,
birds,andcattle as intermediate host.
Gametogony,syngamy,andsporogony
occur in the final hostwhichpassesoutfully
developedsporulatedoocystsresembling
those Isospora species.
Sporocystswithsporozoitesare ingestedby
the intermediatehostwhere trophozoites
encystinstriatedmuscle,forming
sarcocystsor meischer’stube.
A two-hostlife cycle isalsoinvolvedin
Toxoplasma.Schizogonyandmerogonymay
occur both inthe IH and DH. On the other
hand,oocysts,are producedonlyinthe
intestinal cellsof the DH,whichare animal
underthe Feline Family.Transmissionmay
be eitherbyingestionof sporulatedoocysts
or by merozoites(tachyzoitesand
bradyzoites).

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NDENCARNACION 42