37 



110. Vibrissa^ at moat only one-half the length of the second anteunal joint above 



the level of the front edge of the oral margin 1 113. 



Vibriss;e 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 111. 



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) Uelvosia. 



112. Outer side of hind tibia^ distinctly ciliate with bristles (p. 83) Atacta. 



Outer side of hind tibia^. not ciliate (p. 81) Biomyia, 



113. Ijowest frontal bristles below the base, and usually beneath the middle, of sec- 



ond antennal joint 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 erossvein (p. 120) Euthera. 



115. Cheelvs 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) Acenu/ia. 



Lower front corner of the third antennal joint not j)roduced in the form of 

 a tooth. 



Head, viewed from in front, broader than high, arista bare, or nearly 



so (p. 128) miarella. 



Head higher than broad, arista short haired... (p. 117) Vanderwidpia. 

 11(5. .Second segment of abdomen never beaVing more than four marginal macro- 



eh;et:e 117. 



Second segment bearing at least six marginal macrochietie, hind tibiae out- 

 wardly ciliate with bristles (p. 123) Blephanpeza. 



117. Hind tibiie outwanlly 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) Hyphantropliaga. 



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 vibrissa} as long as at the base of antenu;e, proboscis slender, rigid, 



the labella horny and not thicker than the proboscis (p. 83) Siphosturmia. 



Head at the vibrissas much shorter than at base of antenna^, proboscis robust, 

 ileshy, the la_bella soft (p. 108) Stnrmia. 



121. With at least tm- r re backwardly curving bristles in each of the frontal rows, 



abdomen lar<^ely or wholly opa(iue pollinose 122. 



With only *wt) T>ackwardly curving bristles in each of the fnmtal rows, abdo- 



7c e (i^^ weu, ^Muingydestitute of pollen (p. 123) Paravhwia, 



122..Fronl/1)earing two or three pairs of backwardly curving niacrocha'tio outside 

 of the frontal rows, the anterior i)air midway between the lowest ocelhis and 



base of antenna- (p. 116) Pseiidochtrta. 



Front destitute of such macrocha'ta; (p. 105) Frontina. 



123^ 0cellar bristles present, dii-ected 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 . -SAj-rt? 1^25. 



125. Arista distinctly pubescent, lacial ridges bristly on the lowtoy^ve-sixth. 



(p. 117) Prospherysa. 

 Arista bare, facial ridges at most bristly on the lower three-fifths. 



(p. 118) Tachhia. 



126. Diameter of head at the vibrissa- as long as at base of antenna- 127. 



Diameter of head at the vibrissic much shorter than at base of autennui.. . 128. 



