TABLE OF THE FAMILIES. ;3 



Antennas shorter tlian the thorax, the joints broadly and closely united, 

 without marked constriction, and never hairy or pilose; legs strong-, 

 hind pair more or less dilated ; body thick-set, abdomen ovate; wings 

 broad, bare, the anterior veins stouter, the posterior weak. Black- 

 flies, Buffalo-gnats. ....... Simuliid/e. v3 t' 



12. Wings ovate, distally with ten longitudinal veins and without cross- 



veins ; veins strongly hairy; tibiaj without terminal spurs; small, 

 lepidopter-like tlies, the wings when at rest folded roof-shaped. 



PSYCHODID/E. S ^ 



Wings with cross-veins near the middle. ..... 13 



13. Wings hairy, fringed on the hind margin; mosquitoes. CuLiciDyE. ^ 

 Wings bare; the second vein arises near the middle of the wing. 



DlXI^D^. 2 ^ 



14. Third joint of the antennas complex; basal cells of wing long. . 15 

 Antennae composed of three simple joints, the tliird not annulated or 



segmentated, with or without a dorsal arista or terminal style or 

 arista 18 



15. Empodia undeveloped or bristle-like ; antennas elongate, coinposed of 



four or five joints, without differentiated style or arista ; vertex and 

 front hollowed out transversely between the eyes; eyes of male 



never contiguous 25 



Empodia developed pulvilliform ; third antennal joint more or less dis- 

 tinctly segmentated or annulated ; body not bristly. . . 16 



16. Tegulas rather large; third longitudinal vein furcate; five posterior 



cells always present ; the costal vein encompasses the whole margin 

 of the wing ; proboscis of the female adapted for piercing ; third joint 

 of the antennas with from three to eight annuli, never with style or 



bristle. Horseflies. . Tabanid/i;. ^'f 



Tegulas small or rudimentary ; mostly flower-flies. ... 17 



17. Tibias wholly ■without spurs ; longitudinal veins of the wings usually 



crowded anteriorly,* the posterior ones often weak; the costal vein 

 does not reach beyond the tip of the wing; antennas long or short, 

 with or without a terminal or dorsal arista or terminal style. 



SxRATIOMYIDiTi. 4^ T 



The middle tibia% at least, with distinct spurs ; the costal vein encom- 

 passes the entire wing; third longitudinal vein always furcate ami 

 five posterior cells always present. . . . Leptid-k. /)^ J^Jj^^oi 



18. Antennae apparently single-jointed, with a long bristle ; wings with sev- ' 



eral stout veins anteriorly, and other weaker ones ajiparently con- 

 nected with them; femora flattened, the hind legs long; antenna; 

 situated near the mouth; small, quick-running, hunchl)acked flies. 



rnoTjiD.K. yj 

 Not such flics Ill 



* If very large flics from Central America, compare Acanthomkuiixi-:. LL ^ 



