Introduction to A nimal Morphology. 407 



Order 10. Aphaniptera {Kirby): Fleas — laterally com- 

 pressed, wingless, or with scale-like rudiments, with simple 

 or no eyes, short antennoe, lying in a groove ; labrum none ; 

 mandibles long, slender, saw-like, having between them the 

 needle-like epipharynx. Maxillae short, broad, with long, 

 four-jointed palps ; labium cleft, palp-like, often jointed ; 

 thoracic segments homonomous, discrete ; hind legs saltatory ; 

 larvae white, hairy, footless, worm-like. Blood-sucking para- 

 sites, closely related to Diptera, forming one family Pulicidoe. 

 The labium is distinct (Pulex), or rudimental (Sarcopsylla, 

 the chigoe ; its females burrow in the skin of exposed parts 

 in the West Indies). 



Order 11. Diptera — metabolic, with suctorial mouths, two 

 transparent, mesothoracic wings, with radiate costse, and rudi- 

 mental, often irregular, mesothoracic wings, modified into scale- 

 like or pin-like halteres, or balancers ; eyes two, very large ; 

 ocelli three, vertical; neck slender. The mouth is a proboscis, 

 of which the labrum and labium each make make half-tubes ;* 

 the maxillae (^scalpella), mandibles {culielli), are bristle-like, 

 or knife-like, accessory organs, and the former always bear 

 palps. There is also in the last a median sharp epi- 

 pharynx {glossarium). The labial palps are absent, but 

 the maxillary palps often appear (Fig. 45.) 



as labial (Stratiomyidae, Muscidae). 

 The antennae are single, pecti- 

 nate, or short, three-jointed, with 

 a bristle {arista) at the tip, which 

 may be naked {arista yiuda), or 

 hair-clad (pitosa), or terminal (api- 



Caiis), or dorsal (dorsalis). The PlanofWingof Dipteron: i, An- 



, 1-11 tenor basal cell ; 2, hinder marginal 



prOthOraX fused with the strong cell ; 3, third basal ccll ; 4, second 



,, i-rii . . T • 1 1 basal cell; 5, discoidal cell ; 6, axil- 



meSOthOraX. I he Wmg is divided lary cell; 7, lobe ccll; 8, sub-mar- 



by its costffiinto celluli (Fig. 45), t^u!^; ^^.^^^c^^^tl 

 and at its base has two lobes, an TnSuX'a^^c^k^f iSl ^osu; 

 alula and a squama, the latter over '^' discoidai costa ; z, i, uniting cos- 



^ tse; ;>,postical costa; K, anal costa; 



the halteres ; the foot ends in two ^> axillary costa. 



claws, with one or more intervening cushions or pulvilli, 



* That of the labrum = valvula, of the labium = vagina, with often a 

 temiinal lip, capitulum. 



