I. -Hind tibire vvitli spurs at their tips (sometimes small). (Pdugordncc.) . . . .'.. . . .2 



Hind tibiit without spurs; ocelli absent. ( Tabmdna;.) 5 



2. — Third joint of the antennx- composed of t-is^ht aniiuli, the first of which is only a 



little longer than the followin'^;' ones 3 



Third joint composed of five or fewer segments, the first of which is much longer 



than the following; ocelli present 4 



3.— ^Front of female narrow, without denuded callus; ocelli rarely absent.. Pangonia. 



Front of female broad, with a large, broad, denuded callus; ocelli present 



Apatolestes, g. u. 



4. —Second joint of the antenn;x: al)out half as long as the first; wings hyaline or wiih 



small spots; eyes in life with numerous small dots Silvius. 



Second joint as long, or but little shorter than the first; wings with a dark pic ure; 

 eyes in life with fewer, larger spots Chrysops. 



5. -Front of the female as broad as lon^;; callus transverse; front tibi^ie a little 



dilated; base of third antennal joint not dilated Haematopota. 



Front of female narrow 6 



6. — Front tibi.^e very much dilated; third antennal joint not strongly angulated above 



Lepidoselai/n . 



Front tibiae moderately dilated ; face short Diachlorus. 



Front tibiae not dilated 7 



7.— A small ocelligerous tubercle present in tlTe female; eyes pubescent, more dist- 

 inctly in the male Therioplectes. 



Ocelligerous tubercle absent; eyes pubescent Atylotus. 



Ocelligerous tubercle absent; eyes bare Tabanus. 



LEPTIDiE. 



Third joint of antennce simple ; ivitii a simple^ or ihicktuai stvliform, 

 bristle; tegulcp rudimerttary. 



Rather small to rather large species; thinly pilose, with short thorax, 

 elongate abdomen and large wings. Head short, eyes of male contiguous 

 or approximate; ocelli present. Antennae mostly short, never elongate, 

 the third joint with a terminal or dorsal bristle, or terminal slentler style. 

 Face small, excavated. Proboscis short; palpi slender, porrect, often 

 bushy pilose. Abdomen elongate, broadest toward the base, composed 

 of seven segments; the female ovipositor pointed. Legs slender, the hind 

 pair somewhat elongate; some or all the tibiae spurred. Posterior cells of 

 wings all open. 



Larvce carnivorous, living in earth, decaying wood, dry sand, 

 in moss or in water. I'he flies are usually found about meadow 

 and low woodlands, on bushes, etc., and prey upon other insects. Some 

 western species of Symphoromyia, according to Osten-Sacken, suck blood, 

 as do the horse-flies. 



