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A Handbook of Biology

FËMÅLË RËPRØDÜÇTÏVË SÝSTËM:

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It consists of 2 large ovaries, oviducts, spermatheca, genital chamber,

colleterial glands, etc.

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Ovaries lie laterally in the 2^nd – 6^th abdominal segments. Each ovary is

formed of 8 ovarian tubules (ovarioles), containing a chain of developing

ova.

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Oviducts of each ovary unite into a single median oviduct (vagina)

which opens into the genital chamber.

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A pair of spermatheca is present in the 6^th segment which opens into the

genital chamber.

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Sperms are transferred through spermatophores. Their fertilised eggs

are encased in oothecae.

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Ootheca is dark reddish to blackish brown capsule, 8 mm long. Females

lay 9-10 oothecae, each contain 14-16 eggs.

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Development of P. americana is paurometabolous, (development

through nymphalstage).

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Nymphs look like adults. They moult 13 times to reach the adult form. The

next to last nymphal stage has wing pads. Only adult cockroaches have

wings.

ËÇØÑØMÏÇ ÏMPØRTÅÑÇË ØF ÇØÇKRØÅÇH

They are pests because they destroy food and contaminate it with their

smelly excreta. They also transmit bacterial diseases like cholera, typhoid,

tuberculosis, etc.

Notes