130 



Psyche 



[August 



of the body are being placed in preparation for exerting the power 

 to force the body forward. The labrum is then relaxed and the 

 larva darts forward in a rapid wriggling motion. On the under 



Fig. 1. Ctenocephalus felis, head of larva: A, ventral view; B, lateral view; C, 

 dorsal view; ant., antenna; lb., labium; Ibr., labrum; Jiix., maxilla; mx. pi., max- 

 illary palpus. 



side of the labrum is a curved row of bristles which partially line 

 the upper surface of the mouth and when closed meet the bunches 

 of bristles on the ends of the maxillae, thus holding the food in 

 place in front of the mandibles. 



The biting mandibles (Fig. 2 A), which are situated well inside the 

 mouth, are strongly chitinized, broad and triangular and seem to 

 be very powerful for such a larva, appearing more like those of 

 Coleoptera than Diptera. The outer small end tapers gradually 

 back and ends in a broad base with a single large lobe. The teeth 



appear, when the 

 mandibles are in 

 normal position, 

 to be situated, 

 not on the inside 

 edge but some- 

 what back and 

 on opposite sides 

 of each mandible. 

 Thus, when the two mandibles are closed, they overlap each 

 other. The teeth, six in number, are blunt and not sharp, as 

 Kiinckel states, nor do the mandibles end in a sharp point. The 



Fig. 2. C^ewocej?/jaZM5, mouthparts of larva. /I, mandibles; 

 B, maxilla from inner side; C, maxilla from outer side; 

 D, labium. 



