Tune-Oct., 1921 Bulletin of the Brooklyn Entomological Society 69 



head, position of antennae and length of arista similar to 

 the Xylota t3'pe (figure 4), but the face is broadly covered 

 with loose pile (Milesia only) Milesinae. 



- Length of post stigma one and one-half times or less that of 



width, and otherwise without above combination of char- 

 acters 8. 



8. Third longitudinal vein with a deep downward loop into discal 



cell; face, except for a medium stripe, clothed with long 

 pile; sixth vein entering margin of wing a short distance 

 beyond anal cell, i.e., usual distance ; thorax never bearing 

 bristles ; marginal cell closed in Eristalis and Meromacrus. 



Eristalinae. 



- Third longitudinal vein usually straight, but in such cases 



where it is looped downwards {Pterallastes and Teuchoc- 

 nemis) the face is bare, except for a few hairs along eye 

 margins, and sixth vein is prolonged well forward beyond 

 anal cell. (The bare face also excludes Tropidia and 

 Syritta from Eristalinae, while the bristles on the thorax 

 and the brassy color excludes Chrysochlamys) 9. 



9. Anterior crossvein placed before middle of discal cell; third 



vein always straight; antennae sometimes with terminal 

 style ( Callicera and Pelecocera) Chilosinae. 



- Anterior crossvein joining discal cell at or beyond middle; 



face rarely covered with pile and in such cases third vein 

 is always straight Xylotinae. 



Remarks on the family, subfamilies and genera. 



The present paper is the outcome of a search that was made 

 for characters which would more clearly show from which fam- 

 ily, or group of families, the Syrphidae were derived, and to what 

 group it gave rise, if any. The quest in this direction has, so far, 

 given meager results. Apparently the existing families of Dip- 

 tera are, for the most part, so isolated from each other that it is 

 impossible to closely trace true lines of descent. 



The long anal cell, extending nearly to the wing margin, un- 

 doubtedly connects the Syrphidae to those families of the Brachy- 

 cera that have a long anal cell. Likewise the broad, flat abdomen, 

 common to most Syrphidae, with the sides of the tergites not 

 folding downwards and under, indicate close affinities to the 

 Brachycera. But between its closest allies of the Brachycera, 



