116 



ESSENTIALS OF ZOOLOGY 



Y/X 



Labium Maxilla 



Palp. 



elements of which are called the lacinia (inner) and the galea 

 (outer) ; and of an exopodite of five segments forming the palp. 

 The second pair of maxillae are fused together basally to 

 form the posterior or lower lip, the labium, of the mouth. 

 The fused protopodites consist of the submentum and the 

 mentum, and the latter bears the endopodite, which is divided 



into the ligula or 

 Labrum lacinia (inner) and the 



%/ TI 



paraglossa (outer) and 

 an exopodite of three 

 segments, the palp. 

 On the floor of the 

 mouth a chitinous 

 structure is present, 

 termed the lingua, or 

 hypopharynx. 



The neck is narrow 

 and tubular, and its 

 cuticle is thin except 

 in six small patches, 

 which are termed scle- 

 rites. 



The thorax consists 

 of three rings, or seg- 

 ments, with intervening 

 thin connexions. The 

 dorsal part of the ring 

 in each is called the 

 tergum or notum, and 



the ventral the sternum. The pronotum is very large, 

 forming the prominent anterior segment of the body. The 

 mesonotum and the metanotum are about equal in size. 

 The legs are borne by these segments, one pair on each. 

 The legs are jointed, the segments varying in length. In 

 Blatta and its allies the proximal segment, the coxa, is 

 characteristically large, and the tibia is armed with spiny 

 outgrowths. The segments in succession are named coxa, 

 trochanter, femur, tibia, and terminally there is a six-jointed 

 tarsus, the last of which bears the two claws (fig. 58). 



Labrum 



Labium 



Mandible 

 Maxilla 



Hypopharynx 



Fia. 56. Blatta. The upper figure shows the 

 mouth parts in position. The lower 

 figure is a plan of the mouth parts. 



