TACHINID.E. 373 



101. Hind tibiae not with distinct cilia externally. . . . 102 

 Hind tibiae ciliated externally; apical cell open (6). Atacta. 



102. Apical cell open. Biomyia. 



Apical cell closed (108). . . . Pseudotractocera. 



103. Cheeks less than one-third as broad as eye-height; arista thick- 



ened almost to tip (89) . ... Melanophrys. 



104. Frontal bristles in two rows (110). . . . Senotainia. 

 Frontal bristles in four rows (72, 75) . Pachyophthalmus. 



105. Vibrissae at most only one-half the length of second antennal 



joint above oral margin. ....... 108 



Vibrissae at least the length of second antennal joint above oral 

 margin. .......... 106 



106. Ocellar bristles directed forward 107 



Ocellar bristles wanting. ...... Belvosia. 



107. Hind tibiae externally ciliated (6). .... Atacta. 

 Hind tibiae not ciliated. ...... Biomyia. 



108. Lower frontal bristles below base of second antennal joint. 



Siphosturmia. 

 Lowest frontals not below base of second joint (89) . 



Melanophrys. 



109. Palpi absent or vestigial (77) Linnsemyia. 



Palpi present. ......... no 



no. Sides of face at narrowest part less than one-third the width of 



the median depression. . , . . . . . 114 



Sides of face half as wide as the median depression, or more, in 



in. Dorsum of abdomen without macrochaetae. Mystacomyia. 



Dorsum of abdomen with macrochaetae. . . . . 112 



112. Face in profile convex Macromeigenia. 



Face in profile perpendicular. . . . . . . 113 



113. Abdomen with marginal macrochaetae only. . Bolomyia. 

 Abdomen with discal and marginal macrochaetae. 



Paramesochaeta. 



114. Bend of fourth vein with a long appendage; second and third seg- 



ment of abdomen usually without discal macrochaetae (IOI) . 



Nemorsea; 



Bend of fourth vein at most with an extremely short appendage. 



second and third segments of abdomen with discal macrochaetae. 



Panzeria. 



115. Eyes hairy. ......... 116 



Eyes bare 121 



116. First vein with two or more bristles on outer half. 



Exoristoid.es. 

 First vein bare. ......... 117 



117. Abdomen bright or bluish green; facial ridges never bristly on 



more than the lowest fourth (56) . . . Gymnochaeta. 



Abdomen black or more or less yellow. . . . . 118 



118. Facial ridges not bristly on more than the lower half. . 119 

 Facial ridges bristly on at least the lower two-thirds. . 120 



