620 



ZOOLOGY 



SECT. 



lurking-places in the day-time, and is almost omnivorous in its 

 diet. It is a good example of the Insecta, not only on account of its 

 large size, which renders it convenient for dissection, but also 

 because of its generalised structure, which makes it a fairly 

 central member of the class, devoid of any extreme modifications. 

 Three regions are very distinctly recognisable in the body of 

 the Cockroach (Fig. 491). In front is the head, elongated verti- 

 call}', bearing the very long slender feelers or antenna: and the 



Fig. 4fil,— Periplaneta orientalis, male. A, dorsal view. B, ventral view x2^. aW. alfl- 

 aJA aiiiu. first, second, ninth, and tenth segments of abdomen ; ant. anteinife ; c. ecrci ; rJ, 

 clypeus ; ex. coxa of third leg ; K eye ; el. elyti-a ; ep. epicranium ; /. fenestra ; fe. femur of 

 third leg ; hd. head ; l(f\ IgK tg'^. legs ; l.p. labial palp ; Ir. labrum ; mn. mandible ; m.p. 

 maxillary palp ; p.p. style on ninth abdominal segment, internally to which a podical plate 

 is seen ; th^. (th. in B) th'^. tlfi. segments iof thorax ; ti. tibia ; (r. trochanter ; ts. tarsus ; 

 w. posterior wing. 



large eyes, and contracted behind to form a narrow neck. In the 

 middle is the thorax, consisting of three segments, bearing the 

 three pairs of legs and the two pairs of wings. Behind is the 

 aldomen, consisting of ten segments covered over above by the 

 wings in the male. The entire surface is invested by a chitinous 

 cuticle, which is especially thickened on the head, on certain 

 parts of the thorax, and on the anterior pair of wings. 



The head consists of four parts — the epicranium behind, com- 

 prising the region between and behind the eyes ; the clypeus, 

 or portion extending vertically downwards ; and two lateral parts, 



