of spermathecae is present in the th segment, which opens by a median aperture in the dorsal wall of the genital pouch. During copulation, the ova descend to the genital chamber, where they are fertilized by the sperms. A pair of white and branched collaterial glands present behind the ovaries forms a hard egg case called Ootheca around the eggs. Genital pouch is formed by the th , th and th abdominal sterna.
The genital pouch has two chambers, a genital chamber into which the vagina opens and an oothecal chamber where oothecae are formed. Three pairs of plate like chitinous structures called gonapophyses are present around the female genital aperture. These gonapophyses guide the ova into the ootheca as ovipositors. (Figure .
). Ootheca is a dark reddish to blackish brown capsule about 12mm long which contains nearly fertilized eggs and dropped or glued to a suitable surface, usually in crack or crevice of high relative humidity near a food source. On an average, each female cockroach produces nearly – oothecae in its life span of about one to two years. The embryonic development occurs in the ootheca, which takes nearly – weeks.
The development of cockroach is gradual through nymphal stages (paurometabolus) . The nymph resembles the adult and undergoes moulting. The nymph grows by moulting or ecdysis about times to reach the adult form. Many species of cockroaches are wild.
About cockroach species out of , are associated with human habitats. About four species are well known as pests. They destroy food and contaminate with their offensive odour. The mere presence of cockroaches is a sign of unhygienic condition and they are also known to be carriers of a number of bacterial diseases.
The cockroach allergen can cause asthma to sensitive people. Figure . Periplaneta americana reproductive system 7HVWLV 3KDOOLFJODQG 6PDOOWXEXOHV /RQJWXEXOHV 6HPLQDOYHVLFOH 9DVGHIHUHQV (MDFXODWRU\GXFW 5LJKWSKDOORPHUH 9HQWUDOSKDOORPHUH $QDOFHUFXV &DXGDOVW\OH /HIWSKDOORPHUH 7LWLOODWRU 3VHXGRSHQLV 0DOH )HPDOH 2YDU\ 2YLGXFW &RPPRQRYLGXFW RUYDJLQD 6SHUPDWKHFD *RQDSRSK\VHV &ROODWHULDOJODQGV 9HVWLEXOXP *HQLWDOFKDPEHU *HQLWDO SRXFK XI Std Biology-Zoology Chapter- species, is