E. T. CRESSON, JR. 29 



face generally convex; the Micropezidae are slender, long-legopd 

 Hies without preapicals and the third and fourth veins converging; 

 all the other acalyptratae have distinct vibrissae, or the auxiliary 

 vein incomplete or coalescing with the first. 



In the course of my studies it soon 1 ecame evident that several 

 closely allied genera possessed in common distinctly white arista, 

 which were either microscopically, or densely long, white plumose, 

 while other allied genera have the arista black, bare to densely 

 black plumose. 'These characters are also correlated with others 

 of more structural nature, and seem to be of such taxonomic value 

 that I have allowed them to influence me in the definition of 

 some of the tribes. I have recognized three subfamilies, one of 

 which includes the genera Dryomyza and Neuroctena. The species 

 of these genera are surely related to some of the allies of Sciomyza. 

 A few remarks regarding this matter ai"e given under those genera. 

 The remaining, more typical sjiecies are grouped under the two 

 subfamilies as recognized l)y Hendel, w^hich are so considered 

 here without further analysis. 



Synopsis of the Subfa/idlies 



Pro])Ieiiral bristle present; femora without well develo[)ed bristles, but 

 generally pilose; sternopleura with several bristles along upper margin; an- 

 tennae short Dryomyzinae 



Propleural bristle present; femora with well developetl bristles; sccoiul 

 antennal joint short Seiomyzinae 



Propleural bristle absent; second antennal joint enlarged or elongate. 



Euthycerinae 



Further and more extensive stiuly of the genera and species of 

 this family will, no doubt, show reasons to revise the above char- 

 acte]-istics, but, from my study, these offer very agreealjle group- 

 ings. The presence or absence of the proplein-al bristle seems, 

 in the main, to correlate with the antennal development, but in 

 some genera of the Euthycerinae this does not hold. When we 

 get to Sepedon, the antennae become very elongate, with the 

 second joint very much so, and, with the exce})tion of one species, 

 this is very slender and cylindrical. 



Key to Genera 



1. Arista black, bare, pubescent or i)lumose 2 



Arista white on apical portion, bare or pubescent 1,5 



TUANS. AM. ENT. SOC, XLVI. 



