TABLE OF FAMILIES. 



67 



terminal spurs. Small or minute, moth-like flies, the wings 

 when at rest folded roof-shaped; rarely (Phlebolomus) blood- 

 sucking Psychodidae, 92. 



Anterior cross-vein near middle of wing, distinct; second basal 

 cell large and distinct; wings not folded roof-like when at 

 rest 11 



11. Wings tomentose; fringed on the hind margin; antennae of male 



usually bushy plumose; the second and third veins separate at 

 an acute angle. For the most part blood-sucking flies; mos- 

 quitoes Culicidas, 96 



Wings bare; the third vein arises from the second near the middle 

 of the wing, apparently continuous, the second vein arching 

 suddenly forward; never blood-sucking in habit. Dixidae, 94 



12. Wings with a spider-web-like secondary venation. 



Blepharoceridse, 148 

 Wings not with such secondary venation. .... 13 



13. Coxae much elongate (moderately so in the Sciarinae) ; antennae 



usually elongate, the joints usually with constrictions between 

 them; three or two ocelli present; in the latter case one situated 

 near each eye and sometimes perceptible with difficulty; rarely 

 the ocelli appear to be entirely absent; no sexual holopticism; 

 all the tibiae spurred; second basal cell never complete. 



Mycetophilidse , 131 

 Coxae short; the thorax not strongly arched above; antennae usu- 

 ally shorter than the thorax and closely jointed without marked 

 constrictions, sometimes 14-16 jointed, longer and slender; legs 

 usually strong, the pulvilli usually present (Bibioninae) ; eyes 

 of male often large and holoptic; second basal cell often com- 

 plete. ... .... Bibionidae, 140 



AA. BRACHYCERA. 

 Anal cell closed before the border of the wing or distinctly narrowed 

 in the border; if absent or very short the antennce are composed of 

 two or three simple joints ivith or without a style or arista. Palpi 

 rarely elongated, never with more than one freely articulated joint, 

 that is tivo-jointed or one-jointed or absent. Antenna:: (a) elongate, 

 composed of distinctly separable joints, the joints of the flagellum ho- 

 momorphous and sometimes as many as thirty in number; (b) com- 

 posed of not more than ten closely united joints without style; (c) 

 the so-called third joint is complex, that is, composed of from four 

 to eight segments or annitli, the distal one or ones usually differ- 



