122 TtlE CANADIAN ENTOMOLOGlSt. 



Eristalis Meigenii, O. S., West. Dipt. 337 (Yukon River). 



Xylota barbata, Loew, Cent, v., 40 (Sitka). 



Since none of the species taken by Prof. Dyche duplicate those 

 above, the total number of Syrphidae known from Alaska is brought up to 

 twenty. 



These species are included in their systematic relation below. It 

 has been thought best, however, to place them in ensfemble form here. 



Chilosia gracilis, n. sp. 



Chilosia plutonia, n. sp. 



Chilosia a/askensis, n. sp. 



Melanostoma me/linum, Linn. I have also seen specimens of the 

 species taken at Ft. Wrangel by Prof Wickham. 



Syrphus intrude/is , O. S. 



Syrphus inentalis, VVilliston. 



Syrphus protrittis, O. S. 



Syrplius Lesueurii, Macq. 



Syrphus umbellatarum, Schiner. 



Eristalis occideutalis, Williston. 



Helophilus laiifrons, Loew. 



Helophilus Dychei, AVill. 



Xylota ejtiJicida, Say. 



The preponderance of Chilosia and Syrphus foruis which are known 

 to be mountainous is conspicuous ; that the three species of the former 

 genus are all new is not surprising considering the state of our knowledge 

 of them in this country. The occurrence of three European species out 

 of the relatively small total number is rather remarkable, and bears out 

 the law of the occurrence of such forms in the West rather than in the East 

 of this country, or at least that where they occur in the East they also 

 occur in the West. That two species of Helopliihis should be found is 

 entirely as would be expected of such a northern genus ; although that 

 one of them should be new, and that in a restricted group of northern 

 forms, which are of almost circumix)lar distribution, is noteworthy. 



All of this Alaskan material was placed in the form of a rough draft 

 of a paper by Dr. Williston. In a most truly generous spirit he turned 

 the paper with the specimens over to me, advising me to make any 

 changes that I might see fit, and giving me full permission to incorporate 

 it in the present paper. This has been done. The additions of mine 

 are the preceding part, the descriptions of the three new species of 

 Chilosia, and several notes. 



