110. 
37 
Vibrisse at most only one-half the length of the second antennal joint above 
the level of the front edge of the oral margin..-.......-.-..----.--.--- 113; 
Vibrisse at least the length of the second antennal joint above the level of the 
oral margin, frontal bristles descending below middle of the second antennal 
p Ola be rmeeneri oar aot ayate an arse sao eemeaie ae weep aie Sociales Sac ciccamas cose bbl 
111. The ocellar bristles present, directed obliquely forward, facial ridges never 
bristivon more tian! the lowest tourtlins-... 25-226 - 2-2 c2--6 = 26 os 112. 
The ocellar bristles wanting, facial ridges bristly on at least the lowest third. 
(p. 84) Belvosia. 
112. Outer side of hind tibize distinctly ciliate with bristles.......... (p. 83) Atacta. 
Outersideror hind tibice mot culate s: ss. 42 c2-scsnec ea. 2-1 oe (p. 81) Biomyia. 
113. Lowest frontal bristles below the base, and usually beneath the middle, of sec- 
Gries CIN ey OLMibeeree rs cies oe ae cep. ero 2 Sea eer so sme eae a eiatmsi = ee Sele 116. 
Lowest frontals not below base of second antennal joint.......----.------ 114 
114. Facial depression destitute of a median carina ............--...----.----- 115. 
Facial depression with a high median carina, apical cell closed, the petiole 
twacevas; lone as the smallicrossvein —- 22.55.42. 02+ - -- 222 (p. 120) Euthera. 
115. Cheeks about as broad as the eye-height ..-...-.-.-..----- (p. 85) Melanophrys. 
Cheeks less than one-half as broad as the eye height. 
Lower front corner of the third antennal joint produced in the form of a 
sharprtoothi sss ssceseoscee ces oe ce weieee aoe ences enc ses (p. 115) Acemyia. 
Lower front corner of the third antennal joint not produced in the form of 
a tooth. 
Head, viewed from in front, broader than high, arista bare, or nearly 
OMe ee eet eens cele s ra cee Seen St a roa ere (p. 128) Hilarella. 
Head higher than broad, arista short haired. -..(p. 117) Vanderwulpia. 
116. Second segment of abdomen never bearing more than four marginal macro- 
NENT OS ase oc SORE Wee ee ae ne oe ee a eae ee son clita 
Second segment eariie at Teast six mene macrochete, hind tibie out- 
Wanye ciate hha pristless ssa. sss onae sae sees saa r (p. 128) Blepharipeza. 
Le indsbibies outwardly ciliate with bristles’: 2220.25.25 +----2----++--=- ---- 118. 
EGON Ole NO UCUIAtS Pea ee oe ote ne Sea cee nn te ase ae ee Beno 1ar 
118. Bristles of cheeks covering at least the lower three-fourths ........--...-- 119. 
sristles of cheeks covering less than the lower half... .(p. 91) Hyphantrophaga. 
119. Facial ridges bristly at least almost to the middle..-._...........-....-.. 121. 
Facial ridges bristly on less than the lowest fourth.-.........-.--..-.---- 120. 
120. Head at the vibrissie as long as at the base of antenn:e, proboscis slender, rigid, 
the labella horny and not thicker than the proboscis....(p. 85) Siphosturmia. 
Head at the vibrissee much shorter than at base OF oa we, proboscis robust, 
Meshes exlubellaiSOltiten asses tee sree. cla ee aces sites ee ces (p. 108) Sturmia. 
121. With at least three backwardly curving bristles in each of the frontal rows, 
abdomen largely or wholly opaque pollinose...-....---.---..----------- 122. 
With only two backwardly curving bristles in each of the frontal rows, abdo- 
men shining, destitute of pollen. .----.........-..-.-----.(p. 123) Paracheta, 
122. Front bearing two or three pairs of paekwardly curving macrochiets outside 
of the frontal rows, the anterior pair midway between the lowest ocellus and 
DASE ONFATNLE MM ee tee Oe Pay H oice bie aesic cece cee taseee (p. 116) Pseudocheta. 
Front destitute of such macrochets........-:.-----.---2-+< (p. 105) Frontina. 
123. Ocellar bristles present, directed obliquely forward........----.---------- 124. 
Ocelilmbristl espwamiuin ees 2.2 seas eter ose aoa he oseaplee (p. 84) Belvosia. 
124. Bend of fourth vein destitute of an appendage........---..--------------- 126. 
Bend of fourth vein bearing an appendage or distinct fold........---.---- 125. 
125, Arista distinctly pubescent, facial ridges bristly on the lower five-sixth. 
126. 
(p. 117) Prospherysa. 
Arista bare, facial ridges at most bristly on the lower three-fifths. 
(p. 118) TLachina. 
Diameter of head at the vibrissie as long as at base of antenniw.----.----- 127. 
Diameter of head at the vibriss much shorter than at base of antennie... 128. 
