IX. — The North American Species of Conops. By S. W. 

 WiLLISTON, M.A., M.D. 



Of the fourteen species of Conops recorded in Baron Osten- 

 Sacken's valuable catalogue of Nortli American Diptera, but four are 

 designated by the author as having been recognized, viz : excisKS 

 Wied., f/enuaUs Loew, jnctiis Fab., and sfUfittarius Say. As to the 

 last, it is, however, most probable that the species really recognized 

 was tibialis Say, our most common one, and which had been con- 

 founded by both Wiedemann and Loew, and re-described by both as 

 nigricornis Wied., the real Sagittarius being possibly desciibed anew 

 as gemtalis Loew, which I believe to be its synonym. C. pictus is 

 unknown to me ; its recognition must depend upon that of its syn- 

 onym, Ramondi Bigot (teste Loew, vide Osten-Sacken's Catalogue), 

 as the original description of Fabricius is wholly insufficient. In the 

 present paper all of the recognizable descriptions, whose habitats are 

 creditably referred to North America, have been determined with 

 sufficient certainty, except gemialis Lw., and castanopterus Lw., 

 both of which I believe to be of doubtful value. (J. cethiox)S Walker 

 has been recognized with as much certainty as most of the descrip- 

 tions of that author will admit of, while none of Macquart's very 

 insufficiently described species have been recognized, nor the South 

 American species identified by him as also pertaining to North 

 America. ? Conops quadrhnacidatus A^\\mG2L(\.\% a syrphid, proba- 

 bly a Bacha. 



The material herein described has been wholly derived from Mr. 

 Burgess, to whom my sincerest thanks are due, and my own collections. 

 Although by no means so large as I desired, it is, I tnist, siifficient 

 to remove many of the obstacles to the future study of our species. 

 The indiscriminate description of new species, without a considerable 

 knowledge of allied species, is here especially to be deprecated ; and 

 owing to the great individual variation of color, and the paucity of 

 plastic characters, large collections will be essential, eventually, to a 

 complete and satisfactory knowledge. 



Trans. Conn. Acad., Yori. IV. 43 March, 1882. 



