ENDOPTERYGOTA 



Order APHANIPTERA (Fleas) 



441 



Wingless insects, ectoparasitic on warm-blooded animals; laterally 

 compressed with short antennae reposing in grooves; piercing and 

 sucking mouth parts, maxillary and labial palps present; coxae large; 

 tarsus five -jointed ; larva legless; pupa exarate, enclosed in a cocoon. 

 These insects are perfectly adapted to an ectoparasitic existence 

 by their laterally compressed bodies, prominent tarsal claws, well- 

 developed legs suitable for running between the hairs of their host 



Fig. 327. The life history of the flea, Ctenocephalus canis. From Imms, 

 after Howard, a, egg; b, larva in cocoon; c, pupa; d, imago; e, larva of flea, 

 Ceratophyllus fasciatus ; f, antenna of imago. 



and for jumping, and by their mouth parts (Fig. 327). They only 

 exhibit slight relationship to one other order, viz. Diptera, by their 

 metamorphic features and to a less degree by their mouth parts. 



The mouth parts consist of a pair of long serrated mandibles, a pair 

 of short triangular maxillae with palps, and a reduced labium carrying 

 palps. There is a short hypopharynx and a larger labrum-epipharynx 



