THE CHRYSOTOXINE SYRPHID-FLIES 



By Raymond C. Shannon 

 Of the Bureau of Entomology, United States Department of Agriculture 



The material belonging to the genus Chrysotoxum at my disposal, 

 mainly that in the National Collection, has permitted a fairly com- 

 plete review of the American species and a partial review of the 

 European fauna, the results of which are here given. Notes on the 

 types of derivatu-m Walker and viUosulum Bigot, the material re- 

 corded in the Biologia Centralia-Americana (all in the British 

 Museum), and the material recorded by Giglio Tos in the "Ditteri 

 del Messico" (in the Natural History Museum in Turin, Italy) are 

 likewise included. I have had also the use of paratype material of 

 lyerpJexum Johnson and flmnexnn Johnson, and have obtained cer- 

 tain European species through an exchange with Prof. J. Herve- 

 Bazin. 



I wish to thank Maj, E. E. Austen for permission to examine the 

 material in the British Museum and F. W. Edwards for subse- 

 quently examining and making notes on the tj^pes ; Dr. A. Borelli for 

 permission to examine the material at the museum in Turin; Prof. 

 J. Herve-Bazin for the exchange of material; and C. W. Johnson 

 for the paratypes noted above. 



References to the literature of the genus have been largely limited 

 to the original citations, to the new synonymy, and to Mr. Curran's 

 recent review of the group. ^ 



The species of the genus OhrysotoxuTii are fairly large, wasplike 

 flies of a very distinctive appearance. The genus belongs to the sub- 

 family Syrphinae. It is easily distinguished by the elongate antenna 

 with dorsal arista, the marginated sides of the abdomen and the 

 wasplike body markings. The species in this genus, for the most 

 part, are very uniform in structure and color and are separated with 

 difficult3^ All of the material at hand, American and exotic, was 

 studied in order to work out the relative value of the characters 

 within the genus. The genus may be divided into two subgenera on 



iCan. Ent, vol. 56, 1924, pp. 34-40. 



No. 2637.— Proceedings U. S. National Museum, Vol. 69, Art. II 



2995—26 1 1 



