37 
110. Vibrissa at most only one-half the length of the second antennal joint above 
the level of the front edge of the oral margin 113. 
Vibrissas 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 
joint HI* 
111. The ocellar bristles present, directed obliquely forward, facial ridges never 
bristly on more than the lowest fourth 112. 
The ocellar bristles wanting, facial ridges bristly on at least the lowest third. 
(p. 84) Belvosia. 
112. Outer side of hind tibiae distinctly ciliate with bristles (p. 83) Atacta. 
Outer side of hind tibia' not ciliate (p. 81) Blomyia. 
113. Lowest frontal bristles below the base, and usually beneath the middle, of sec- 
ond antennal j oint 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 
twice as long as the small crossvein (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 
sharp tooth (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 
so (p. 128) ffilarella. 
Head higher than broad, arista short haired. ..(p. 117) Yanderwulpia. 
116. Second segment of abdomen never bearing more than four marginal macro- 
ch»t3B... 117. 
Second segment bearing at least six marginal iuacrochsetae, hind tibire out- 
wardly ciliate with bristles (p. 123) Blepharipeza. 
117. Hind tibiae outwardly ciliate with bristles 118. 
Hind tibia' not ciliate 123. 
118. Bristles of cheeks covering at least the lower three-fourths 119. 
Bristles of cheeks covering less than the lower half. .. .(p. 91) Hyph«ntrop>haga. 
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 vibrissas as long as at the base of antenna', proboscis slender, rigid, 
the labella horny and not thicker than the proboscis. . . .(p. 83) Sijphosturmia. 
Head at the vibrissa much shorter than at base of antenna', proboscis robust, 
fleshy, the labella soft (p. 108) Stnrmia. 
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) Parachceta. 
122. Front bearing two or three pairs of backwardly curving macrockyet.'e outside 
of the frontal rows, the anterior pair midway between the lowest ocellus and 
base of antenna' (p. 116) Pseudochata. 
Front destitute of such inacroclueta^ (p. 105) Frontina. 
123. Ocellar bristles present, directed obliquely forward 124. 
Ocellar bristles wanting (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. 
(p. 117) Prosplierysa. 
Arista bare, facial ridges at most bristly on the lower three-fifths. 
(p. 118) Tachum. 
126. Diameter of head at the vibrissa- as long as at base of antenna' 127. 
Diameter of head at the vibrissa' much shorter than at base of antenna;.. . 128. 
