12 OHIO BIOLOGICAL SURVEY 



Microdon. Certain of my fellow students have directed me to materials 

 for stud}- and my wife has helped me in innumerable ways. 



Of the literature on this family, the works of Dr. vS. W. Williston 

 have been most useful. His excellent Synopsis of North A7?ierican 

 Syrphidae is indispensable. I have made constant use of it. In Part 

 III, the kej'S to species under each genus are adapted for the most part 

 from this work; being restricted, however, to cover only those species 

 which have been, or seem likely to be, taken in the State. The key to 

 genera is taken almost verbatim from the same author's Manual of North 

 American Diptcra. 



J. M. Aldrich, Catalogue of North American Diptera, lists in some 

 sixt}' pages most of the important papers on this famil}^ which appeared 

 previous to January i, 1904. The student isreferred to it for synonymy; 

 and descriptions wdiich do not appear in Williston's Synopsis will for 

 the most part be cited there. 



The work of Verrall on British Flies is very useful and I am indebted 

 to it for man}' of the notes on metamorphoses and larval habits given in 

 Part II. Other papers to which the Ohio student will most likely wish 

 to refer are listed in a brief bibliograph}-. 



Part I. 



HIvSTORICAL ACCOUNT OF THE FAMII^Y 

 The first of the genera of Syrphidae to be established was Rhingia, 

 described by Scopoli from Europe in 1763. The following year Geoffroy 

 de.scribed a si)ecies of Volucella from Paris. Eleven years later (1775) 

 Fabricius founded the genus Syrphiis and nineteen years after this the 

 genus Ccria. Nothing more of importance was done until 1803 when 

 Meigen described half a score of genera from Europe. 



From 1804 to 1825, Latreille, Fabricius, Meigen, Fallen, Weidemann 

 and St. Fargeau and Serville added several dozen genera; and the 

 latter year Latreille described the first genus (Sphccoviyia) from North 

 America. From 1834 to 1S75, Macquart, Loew, Rondani and Schiner 

 from Europe, Walker from Brazil, and Philippi from South America 

 were the principal students of the family. From 1876 to 1881, Osten 

 Sacken added half a dozen North American genera, while since 1882 

 Williston from North America and Bigot have described a number of 

 new genera and many species. 



Our knowledge of the family in North America is due very largely 

 to the efforts of Meigen, Wiedemann, Saj', Macquart, Schiner, Loew, 

 Osten Sacken, Bigot, Williston, W. A. Snow, W. D. Hunter, R. C. Os- 

 burn, C. H. T. Townsend, C. W. Johnson and D. W. Coquillett. 



