Describe reproductive system of cockroach in detail.

$\rightarrow$ Cockroaches are dioecious and both sexes have well developed reproductive organ.

$(i)$  Reproductive system of male cockroach: Male reproductive system consists of a pair of testes, one lying on each lateral side in the $4^{\text {th }}-6^{\text {th }}$ abdominal segments.

$\rightarrow$ From each testis a thin vas deferens, which opens into ejaculatory duct through seminal vesicle. The ejaculatory duct opens into male gonopore situated ventrally to anus.

$\rightarrow$ A characteristic mushroom-shaped gland is present in the $6^{\text {th }}-7^{\text {th }}$ abdominal segments which functions as an accessory reproductive gland. Other long and flat gland - conglobate gland is located on the ventral side of ejaculatory duct is an accessory reproductive gland. Its secretion makes hard coating around sperm cells bag.

$\rightarrow$ The extemal genitalia are represented by male gonapophysis or phallomere (chitinous asymmetrical structures, surrounding the male gonopore).

$\rightarrow$ The sperms are stored in the seminal vesicles and are glued together in the form of bundles called spermatophores which are discharged during copulation.

$(ii)$  Female reproductive system :

$\rightarrow$ The female reproductive system consists of two large ovaries lying laterally in the $2^{\text {nd }}-6^{\text {th }}$ abdominal segments.

$\rightarrow$ Each ovary is formed of a group of eight ovarian tubules or ovarioles containing a chain of developing ova.

$\rightarrow$ Oviducts of each ovary unite into a single median oviduct which opens into the genital chamber. A pair of spermatheca is present in the $6^{\text {th }}$ segment which opens into the genital chamber.

$\rightarrow$ Egg cells enter into genital chamber during mating. They are fertilized by sperm cells.

$\rightarrow$ Collateral glands present in female cockroach possess secretion. Due to its secretion oothecae is formed.

$\rightarrow$ Fertilised egg cells are encased in capsules called oothecae. Oothecae is a dark reddish to blackish brown capsule, about $3 / 8^{"}(8 \mathrm{~mm})$ long. They are dropped or glued to a suitable surface, usually in a crack or crevice of high relative humidity near a food source.

$\rightarrow$  On an average, females produce $9-10$  oothecae, each containing $14-16 $ eggs.

$\rightarrow$ The development of $\mathrm{P}$-americana is indirect.

$\rightarrow$ Means its development is done by nymphal stage.

$\rightarrow$ The nymph appears like adult insect only. The nymph grows by moulting about $13$  times to reach the adult form. The next to last nymphal stage has wing pads but only in adult cockroaches.