STRUCTURE OF COCKROACH 



373 



Specialised. Their position is among the Orthoptera, in 

 the same order as locusts and grasshoppers. The hatched 

 young are like miniatures of the adults, except that wings 

 are absent. If there are wings, they appear at the last 

 moult, when the cockroach becomes sexually mature. 



Skin. — There is an external chitinous cuticle and a 

 subjacent cellular layer — the epidermis or hypodermis 



Fig. 211. — Ventral aspect of male cockroach with the wings extended. 

 An imaginary median line has been inserted. 



A., Antennae; E., eye; P.T., pro thorax ; W^., first pair of wings; 

 W^., second pair of wings ; C, cercus ; St., style ; Co., coxa ; 

 Tr., trochanter ; F., femur ; Ti., tibia ; Ta., tarsus. 



— from which the cuticle is formed. The newly hatched 

 cockroaches are white, the adults are dark brown. 



Moulting, which involves a casting of the cuticle, of 

 the internal lining of the tracheae, etc., occurs some seven 

 times before the cockroach attains in its fifth year to 

 maturity. 



The muscles which move the appendages, and produce 

 the abdominal movements essential to respiration, are 

 markedly cross striped. They are in many cases attached 

 to special tendons, which arise as cuticular invaginations, 

 and are lost and replaced at each moult. 



