Phallomeres or gonapophyses are structures which
(A) Are found only in male cockroaches
(B) Are found only in female cockroaches
(C) Form the external genitalia in male and female cockroaches
(D) Form the egg shell are present in male cockroaches

Hint: Head, thorax, and abdomen are the three major segments of cockroaches. Cockroaches have an extra sense of ability to pick up smells and vibrations using a long pair of antennae. The antennae of the cockroaches are connected to the head, which additionally includes the brain.

Complete answer:
1.Cockroaches show dioecious properties.
2.Gonapophysis provides the external genitalia and plays an incredible role by assisting in the reproductive system.
3.There are three gonapophysis that can be found in the female cockroach while the male cockroach has six gonapophyses.
4.Male cockroaches have three chitinous structures and they are called phallomere that make the external genitalia of the cockroach. They consist of
a. Right Phallomere,
b. Left Phallomere and
c. Ventral Phallomere
These three phallomere help in opening the gynatrium of the female cockroaches.
The six gonapophysis make the structure of the external genitalia in female cockroaches.
The external genitalia in female cockroaches have an ovipositor developed by two gonapophyses. The ovipositor exists above as well as behind the gonopore.

Hence, the correct answer is option (A)

Note: Cockroaches are usually found in contaminated places. Gonapophysis is a chitinous type structure that can be found in the anal region of cockroaches. The number of gonapophysis in females is almost twice the number of gonapophysis in males. In size, female cockroaches look bigger than male cockroaches.