158 THE COCKROACH 



To see the next three pairs of appendages, fix the animal 

 down on its back by means of a pair of small pins passed 

 through the sides of its prothorax. Bend the ventral part of 

 the head forwards and fix it in that position by means of 

 crossed pins. 



Examine the appendages in situ, noting their positions. 



Remove the whole of the labium (s m to p g, fig. 37) with)ut 

 injury to the structures beneath it. Mount it in glycerine. 



Similarly remove and mount the right first maxilla and 

 the right mandible. 



b. The mandibles are a pair of stout jaws, strongly 



toothed on their inner margins, and working side- 

 ways. They lie immediately below the gense, 

 and articulate with the epicranium and with the 

 clypeus. 



c. The first maxillse are situated behind the mandibles. 



Each consists of the following parts. 



i. The protopodite consists of two joints, the cardo 

 or proximal piece, and the stipes or distal 

 piece. 



ii. The endopodite has two divisions, an inner and 

 an outer. The inner division, or lacinia, is a 

 hard blade pointed at the end, and provided 

 with stiff setee along its inner border. The 

 outer division, or galea, is softer and is elon- 

 gated : on the inner surface of its distal end 

 is an oval cushion covered with short curved 

 stiff setae, and notched to receive the point of 

 the lacinia. 



iii. The exopodite or maxillary palp is a five-jointed 

 palp, borne on the outer side of the distal end 

 of the stipes. Its first two joints are short. 



d. The second maxillae are similar in shape to the first 



maxillffi, but smaller. They are fused together 

 in the median plane by their protopodites, and 

 together constitute the labium or posterior lip. 



