Which of the following mouthparts is considered the primitive condition? A. prognathous B. hypognathous C. opisthognathous D. all of the above Solution Answer: (B) Hypognathous In hypognathous, the long axis of the head is vertical, i.e. at right angle to the long axis of the body. The mouthparts point downwards e.g. grasshopper, cockroach etc. It is considered primitive condition in Insecta..