TABLE OF THE FAMILIES. 5 



Neuration not intricate; anterior cross- vein always distinct; labella of 

 proboscis fleshy 30 



30. The fourth vein terminates before the tip of the wing; male sexual 



organs prominent. ....... APIOCERID^E. 



The fourth vein terminates beyond the tip of the wing; male sexual 

 organs small. ..... ... THEREVID^E. 



31. Antennae with a dorsal arista 37 



Antennas with a terminal arista or style 32 



32. Wings pointed, no cross-veins in the middle, the fourth longitudinal 



vein furcate and arising from the fifth ; small species. 



LONCHOPTERID.E. 

 Wings rounded at the tip, not lancet-like 33 



33. Second basal cell confluent with the discal cell, not separated by a vein, 



the auxiliary vein does not terminate in the costa; small, mostly 



brilliant-colored, predaceous flies. . . . DOLICHOPID.*. 



Second basal cell separated from the discal cell by a vein. . 34 



34. Antennae with a terminal style 35 



Antennas with a terminal bristle. 36 



35. First posterior cell closed (Conopidce pt., Syrphidce, pt.) . . 40 

 First posterior cell open EMPIDJE. 



36. Head comparatively small, the proboscis more or less elongated ; alula 



of wings usually rudimentary EMPID^E. 



Head as broad as the thorax ; proboscis fleshy ; alula distinct. 



PLATTPEZID.E. 



37. Proboscis rudimentary, palpi wanting; first posterior cell usually nar- 



rowed; tegulae usually large. Botflies. . . . (ESTRID^E. 



Proboscis not rudimentary ; palpi present. . . . . 38 



38. Second basal cell confluent with the discal cell, not separated by a 



small vein ; small, mostly brilliant-colored, predaceous flies ; face 



never broad and convex - . DOLICHOPID.E. 



Second basal cell separated from the discal cell by a small cross-vein 

 (if not, not brilliant-colored predaceous flies). ... 39 



39. Basal cells of wing elongate, the anal cell closed toward the margin ; 



first posterior cell closed or much narrowed (except sometimes in 

 Pipunculid(e). . . . . . . . . . . 40 



Posterior basal cell small, the anal cell always closed remote from the 

 margin . . 42 



40. Face with subantennal vertical grooves or depression. . , 42 

 Face convex transversely or with a median ridge; never with a suban- 

 tennal depression. . . . . . . . 41 



