274 



MANUAL OF ELEMENTARY ZOOLOGY 



maxillules of the crayfish are not represented in the 

 cockroach, though in certain primitive insects corresponding 

 structures are present. The maxillse consist of (a) a 

 protopodite of two joints known as the cardo and stipes, 

 (b) a five-jointed endopodite known as the maxillary palp, 

 (c) two lobes — an inner lacinia and 

 a softer outer galea — borne on the 

 stipes to the median side of the 

 palp. Behind the maxillae lie a 

 pair of appendages which corre- 

 spond in position to the first 

 maxillipeds of the crayfish, but 

 are here known sometimes as the 

 second maxillae, though better as 

 the labium. Their protopodites 

 are fused so that they form a single 

 lower lip. The first joint of their 

 common protopodite is the sub- 

 mentum, the second the mentum. 

 This bears on each side an endo- 

 podite or labial palp of three joints, 

 set upon a projection of the 

 mentum known as the palpiger. 

 At the end of the mentum stand 

 two lobes. Their basal parts are 

 fused, liked the protopodites, form- 

 ing a structure, known as the ligula, 

 which is deeply notched at its free 

 end. On each side of the notch it 

 ; bears an inne >: lacinia and an outer 



at., antenna; can., anal paraglOSSa. It Will be Seen that 



thor'aiic'" te\ a gumf\ P ^; the h ead of the cockroach contains 

 mesothoradc tergum ; th. 3, one segment more than that of the 



metathoracic tergum ; wg., c i: 



vestige of fore wing. CraynSn. 



The head is joined by a soft 

 neck to the thorax. This consists of three segments — the 

 Thorax. prothorax, mesothorax, and metathorax. Each 



has a tergum or notum above and a sternum 

 below. The pronotum is the largest and projects in front so 

 as to hide the neck. Each segment bears a pair of legs. The 

 shape of these legs and the names of their joints are shown 



•06.10 



Fig. 178. — A female of 

 the common cockroach. 

 The body is somewhat 

 compressed so as to 

 show the membranes 

 between the abdominal 

 terga. The legs are not 

 in the attitude charac- 

 teristic of the living 

 animal. 



ali. 



