A KEVIEW OF THE SOUTH AMERICAN TWO-WINGED 

 FLIES OF THE FAMILY SYRPHIDAE 



By Raymond C. Shannon 

 Of the Bureau of Entomology, United States Department of Agriculture 



The present contribution to the knowledge of the South American 

 Syrphidae is mainly based on the collection in the United States 

 National Museum. Additional material was borrowed from the 

 British Museum through the kindness of Maj. E. E. Austen. In this 

 material a number of new genera and species have been recognized 

 and are herein described. 



A paper now in press ^ contains a treatment of all the South 

 American Xylotini known to the writer. 



The Syrphidae of Chile have been treated as a unit several times 

 by various authors. A large share of the present material is from 

 Chile, and this has been treated in a separate section of the paper 

 in order to preserve this unity. 



The key which is here submitted for the determination of the 

 genera of South American Syrphidae must be considered as a pro- 

 visional one. The South American fauna is comparatively little 

 known, and very probably many of the genera which exist there 

 still await recognition. Most of the species known from this region 

 were described prior to 1900, when the genera of this familj^ were 

 very imperfectly defined. This complicates the recognition of the 

 old species and genera and makes for instability in the classification. 

 The writer has found that about half of the genera are distinct from 

 the Nearctic genera to which many of the old species had been 

 assigned. 



It is of interest to note that several of the larger genera and 

 groups found in North America and Europe are as 3^et not authenti- 

 cally recorded from South America. These are the Chilosini, Seri- 

 comyinae, Merodon, Eumerus^ and Criorrhini. 



The subfamilies given in the key are the same as those given in 

 my previous key (Reclassification of the Subfamilies, Tribes, and 

 Genera of North American Syrphidae ^) save that Nausig aster is 



> Proe. U. S. Nat. Mus., vol. 69, art. 9. (Published on Dec. 1, 1926.) 

 2 Shannon, Bull. Brooklyn Bnt. Soc, vol. 16, 1921, pp. 67-69. 



No. 2658.— Proceedings U. S. National Museum, Vol. 70, Art. 9 



18121—27 1 1 



