Q6 Bulletin of the Brooklyn Entomological Society Vol. XVI 



Syrphidae present excellent specific characters, there is a remark- 

 able dearth of generic or group characters." 



Metcalf in his "Syrphidae of Ohio" (Ohio State Univ. Bull, 

 xvii, no. 31), the largest treatise to appear on the North American 

 Syrphidae since Williston's Synopsis, also speaks of the great 

 difficulty in breaking up the family into subfamilies. He states : 

 " It seems to me almost certain that a complete study of larval 

 characteristics and habits, together with what is known of the 

 imagoes, will make possible a satisfactory division of this large 

 family into subfamilies, which is conceded impossible from a con- 

 sideration of the imagoes alone. The family characters are sim- 

 ple and very definite. The species are also for the most part 

 reasonably distinct. But the presence of many vexing, inter- 

 mediate forms makes it almost impossible to break the family up 

 into satisfactory subfamilies or in some cases to group the species 

 ' into genera." 



In the present study of the Syrphidae an earnest attempt has 

 been made to discover structural characters for dividing the 

 family into subfamilies which would contain natural groups of 

 genera, and, in addition, to give characters for the definition of 

 the genera themselves. Rather a notable success has been made 

 with one group, namely, the Syrphinae. This group is character- 

 ized by having the humeral calli, and the region between them, 

 destitute of pile ; abdomen of both sexes always composed of five 

 visible segments exclusive of genitalia; and, further, it contains 

 all of the aphidophagous species except those of Pipiza — a bio- 

 logical character of considerable significance. By using these and 

 supplementary characters, given in the table of subfamilies, the 

 Syrphinae, in the old sense, have been split in two ; the genera 

 removed therefrom have mostly been considered here as com- 

 posing the subfamily Chilosinae. By this division the classifica- 

 tion of the Syrphinae and Chilosinae has been greatly facilitated; 

 however, there is still much to be desired in classifying the genera 

 of the Syrphinae, even as they now stand. 



The genus Chrysoioxum, which has been variously associated 

 with Microdon, Sphecomyia and Callicera, and also has been con- 

 sidered as a separate subfamily unto itself, is undeniably a mem- 

 .ber of the Syrphinae. 



