406 FLEAS 



are furnished with rows of stout spines and are armed at the 

 tip with a pair of large stout claws. 



Eyes are present in some species of fleas but not in others. 

 The antennae are short and club-shaped, and when not in use are 

 folded back into special grooves for them on the sides of the 

 head (Fig. 178, ant. gr.). The mouthparts (Fig. 178) are fitted 

 for piercing and sucking. In the normal resting position they ap- 

 pear to consist of a long jointed proboscis, blunt at the tip, with 



\ant. 



FIG. 178. Head and mouthparts of a flea (squirrel flea, Ceratophyllus fasciatus) ; 

 ant., antenna; ant. gr., antennal groove; cox., coxa of 1st leg; cten., ctenidium; 

 hyp., hypopharynx ; lab. palp., labial palpi, which together form a tube for pro- 

 tecting the lancets; mand., mandibles; max., maxilla; palp., maxillary palpi; 

 prothor., prothorax; st. pi., sternal plate of skeleton with which leg is articulated. 



a pair of stout triangular flaps at either side at the base. The 

 triangular parts are the maxillae and each is provided with a 

 stout four-segmented palpus, which might easily be mistaken for 

 an antenna. The proboscis really consists of a pair of segmented 

 gouge-shaped structures, the labial palpi, which fit together to 

 form a more or less perfect tube, in which lie three piercing 

 organs. The latter consist of a pair of thin bladelike mandibles 

 serrated on each edge, curved at the tip, and provided with a 

 longitudinal groove, and a single bristle-like organ, the epiphar- 

 ynx. In piercing the skin of the host the epipharynx first bores 



