324 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



linear than the preceding ; face very much produced, almost conical, as 

 in the description of Syrphus trichopus Thomson (Eugenics Kesa, p. 

 502), which is evidently a Melanostoma. The " thorace haud viridi" of 

 that descrijjtion prevents me, however, from identifying it. 

 Melanostoma sp. — Santa Barbara, Oal., February 10. 



Syrphus. 



I have six Californian species of this genus (in the resticted sense). 

 They all show the greatest resemblam;e either to European species or 

 to species from the Atlantic States. S. pyrastri is not distinguishable 

 from the European species of that name. I have left the name of 8. 

 lapponicus to specimens but very little different from specimens from 

 the Atlantic States which would pass under that name. Whether my 

 8. americamis is the same as the species from the Atlantic States, the 

 discovery of the as yet unknown female will have to prove. 8. intru- 

 dens is remarkably like my 8. amalopis from the White Mountains, but 

 seems to be, nevertheless, a different species. 8. protritus is very like 

 the common 8. rectus and the European ^S*. ribesii, but differs in the 

 coloring of the legs. 



Syrphus affords an interesting field for the study of the limits of varia- 

 tion ; of local, perhaps seasonal varieties. It is very desirable that en- 

 tomologists should collect large numbers in both sexes, and take note of 

 the exact date and locality of each specimen. Until the laws of variation 

 in 8yrpJms are better known, it would be useless to multiply species upon 

 vague and secondary characters. In the present case, as in many others, 

 I have preferred to retain the names of European or Eastern American 

 species whenever the Californian specimens did not show any distinctive 

 characters which I could consider as specific. 



Several of my new species I possess in the male sex only. I have, 

 nevertheless, described them, in the hope that these descriptions, owing 

 to the frequent coincidences with the species from the Atlantic States, 

 would not be unwelcome from one who described the latter. 



For the detailed descriptions of the eastern species, I refer to my 

 paper, "On the North American Species of the Genus Syrphus," in the 

 Proceedings of the Boston Society of Natural History, October 6, 1875. 



8yrplms fumipennis Thomson, Eugenics Eesa, 199 (California), seems 

 to be very near my 8. americamis and opinator, but does not quite agree 

 with either. The slightly brownish tinge of the wings is not a charac- 

 ter to be relied upon. 



I. The three abdominal yellow cross-bands are interrupted (dissolved 

 into lunate spots) : 

 Front very much projecting in both sexes; eyes pubescent; in the 

 male, there is on the eyes a conspicuous area, of larger 

 facets in the. middle ; large species, with three pairs of sub- 

 lunate yellowish-white abdominal spots on velvety-black 

 ground . . 1. pyrastri Lin., i 9 . 



