FAMILY TACHINID.E THE TACflINID« - 439 



142. No hairs surrounding the oral vibrissas which are situated high above 



the oral margin; abdomen long and slender (71, 76). 



Xanthomelana Wulp 

 Vibrissas situated level witli the oral margin, or if somewhat above 

 with a few hairs near their base; abdomen, from dorsal view, spher- 

 ical in outline *Clistomorpha Townsend 



143. Oral vibrissae differentiated; oral margin not rounded anteriorly in 



profile 144 



Oral vibrissas not differentiated, or only very weakly so; head convex 

 below in profile; clypeal region narrow and at least two-thirds as 

 long as upper part of face Eutrixa Coquillett 



144. Costal spine not greatly developed, never longer than the width of the 



costal cell and not conspicuous 145 



Costal spine as long as width of costal and subcostal cells combined; 

 vibrissae level with oral margin; parafacials gently convex in profile. 



Phrynofrontina Townsend 



145. Face strongly retreating, vibrissae level with oral margin or situated 



moderately above; three or four pairs of marginal scutellars and 

 sometimes a weak apical pair which may be cruciate; arista rarely 

 thickened to beyond the middle, the penultimate segment never 



elongate 153 



Face almost as long below as at base of antennae; arista often thick- 

 ened to the apical fourth and with the penultimate segment elon- 

 gate 146 



146. Arista not thickened on its whole length; facial depression not oval 



and deeply sunken 147 



Arista thickened on its whole length; facial depression oval and very 

 deep (89) 3Ielanophrys Williston 



147. Parafacials more or less yellowish in ground color; abdomen usually 



largely yellow and extensively pollinose 148 



Parafacials silvery pollinose on a black ground; abdomen shining 

 black, the sides sometimes broadly red; vibrissae level with oral 

 margin Dionsa Desvoidy 



148. Cheeks more than one-tenth as wide as the eye-height; female ab- 



domen not truncate at apex from lateral view 149 



Cheeks at most one-fifteenth as wide as the eye-height; arista short 

 plumose; ocellars absent or very weak (117) fCalodexia Wulp 



149. Vibrissal angles not approximated, or if so the vibrissse situated level 



with the oral margin 150 



Vibrissal angles conspicuously approximated, the vibrissae situated 

 above the oral margin (92) Chryseria Desvoidy 



150. Anterior crossvein situated half way between the tip of the auxiliary 



and first veins; posterior crossvein but little oblique 151 



Anterior crossvein situated behind the tip of the first vein; posterior 

 crossvein very oblique Catalinovoria Townsend 



151. Vibrissae situated distinctly above the oral margin; oral margin not 



prominent ( 108 ) Viviania Rondani 



Vibrissae level with oral margin 152 



* Curran, 1927, Can. Ent., lix, p. 297. 



t Curran, 1934, Amer. Mus. Novit. No. 685. 



