REVIEW OF THE AMERICAN XYLOTINE SYRPHID- 



FLIES 



By Raymond C. Shannon 



Of ilie Bureau of Entaniologi/, United States Department of Agriculture 



INTRODUCTION 



A revised synopsis of all of the American species of the tribe 

 Xylotini is here presented. It is based primarily upon the extensive 

 collection in the United States National Museum and studies made 

 upon the type material of Syrphidae in the British Museum (Natural 

 History) and the Museum of Comparative Zoology, Cambridge, 

 Massachusetts, further supplemented by the loan of material from 

 various sources. 



The writer wishes to cordially thank the following gentlemen : 

 Maj. E. E. Austen for permission to examine the collection of Dip- 

 tera in the British Museum in which the types of the species de- 

 scribed by Walker, Bigot, and Williston (the Biologia Centralia 

 Americana Syrphidae) are located, for the free use of his manu- 

 script notes pinned in the collection with the specimens and also for 

 the loan of undescribed material; Samuel Henshaw and Nathan 

 Banks for the facilities they afforded the writer while examining the 

 Osten Sacken-Loew collection in the Museum of Comparative Zoo- 

 logy, Cambridge, Mass.; Prof. J. Herve-Bazin, Prof. J. S. Hine 

 and C. W. Johnson for the loan of material ; and Dr. E. A. Schwarz 

 and Dr. J. M. Aldrich for kindly criticism and suggestions. 



Citations relating to synonomy and new species are given only 

 where they are subsequent to the Aldrich (North American Diptera, 

 1905) and the Kertesz (Catalogus Dipterorum, vol. 7, 1910) cata- 

 logues. References are several times made to " The Genitalia of 

 Male Syrphidae " by C. L. Metcalf ^ and papers illustrating pupae 

 of various species of Syrphidae by C. T. Greene.- Locality records 

 are so numerous for Syrphidae, that in order to reduce the space 

 required for them, they have been listed by state only, except in the 

 case of new or little known species. 



lAnn. Ent. Soc. Amer., vol. 14, p. 169, 1921. 

 aProc. Ent. Soc. Wash., 1920-1923. 



No. 2635.— Proceedings U. S. National Museum, Vol. 69, Art. 9. 



3042—26 1 1 



