1875.] 135 [Osten Saeken. 



On the North American Species of the Genus Syrphus 

 (in the narrowest Sense). By C. R. Osten Sacken. 



Among the preliminary work to be gone through before the publi- 

 cation of my intended new Catalogue of the North American Dip- 

 tera, I met with the necessity of settling the nomenclature of some- 

 of the native species of the genus Syrphus, the most, common of 

 which, until now, remained unnamed or badly named in collections. 

 I take this genus in the sense of Schiner, that is, excluding with him. 

 Melanostoma, Platychirus, Xanthogramma, Pyrophsena, Didea, and 

 Mesograpta (Lw.). Of the genus thus restricted, I discuss the ten 

 species hitherto found in the United States, all of which occur ins 

 New England. 



The Syrphidas* are among those families of Diptera in which a 

 large number of species, common to Europe and to North America, 

 occurs. Of the ten species which form the subject of the present 

 paper, six 1 are identical, or very nearly so, with European species. 

 Two of these have been described under new names for America 

 (S. genicwlatus Macq. = umbellatarum Lin.?, and S. diversipes Macq. 

 = cinctellus Zett. ?) ; two others I have described under new names,, 

 for reasons to be given hereafter (S. torvus =: topiarius Zett.; £. 

 rectus zz^rlbem Lin. ?); two. again I considered sufficiently identified 

 to retain them under their European names, (S. abhneviatws Zett., 

 and S. lapponicus Zett.). Of the four 2 remaining, species which, as 

 far as I know, are peculiar to the American continent, two have been 

 described before (S. Lesuewii Macq. and & am<ericrmm Wied.) and 

 the two others I have not been able to identify and therefore describe 

 them as new ($. contumax ami S. amalopis). 



This comparatively small number will probably soon be increased 

 by new discoveries. Still, considering the extent to which the coun- 

 try has been ransacked already,, the increase cannot be expected to. 

 be very large. Dr. Schiner enumerates forty-five species of Syrphus 

 for Austria, and some twenty more for the rest of Europe. The 

 numerical difference in this respect between the two faunas is very 



x More probably seven; S. Lesueurii seems to occur in eastern Europe; I saw a 

 specimen, labelled "Silesia," among some Syrphi from Dr. Zeller's collection, now 

 in Boston, which, apparently, belongs to that species (compare below);. 



* Or three ; about S. Lasueurii see the note above,* 



