Vol. 5, p. 151-153. Mat 22, 1925. Occasional Papers OF THE Boston Society of Natural History. THE GENUS CHALCOMYIA (DIPTERA: SYRPHIDAE). BY RAYMOND C. SHANNON. The genus Chalcomyia Williston (Bull. Brooklyn Ent. Soc, vol. 7, p. 133, 1885) appears to be peculiar to North America. It was erected for Myiolepta aerea Loew and denned principally on the basis of: antenna short, with dorsal arista; marginal cell open; anterior (discal) cross-vein distinctly before the middle of the dis-cal cell, usually rectangular; face black without tubercle; scutel-lum unusually large, nearly square; males dichoptic. The two last characters are peculiar to Chalcomyia, as hitherto known, and easily suffice to define the genus. A second species, cyanea, was added by Smith, although the scutellum in this species is not as well developed as in the geno-type and the face of the male has a slight tubercle. Two addi-tional species are now at hand which are still more aberrant. The one, received from Mr. C. W. Johnson, is represented only by the female and hence one of the generic characters found in the male sex, i.e., dichoptic eyes, is not available. The scutellum is notice-ably broader than long and the discal cross-vein is nearly at the middle of the discal cell. The species is strikingly like the Xylotae and one is at first inclined to locate it in the Xylotinae. However, the discal cross-vein is rectangular as in the Chilosinae and the abdomen is broadly oval and flat as in Chalcomyia aerea female (rather elongate and parallel-sided in Xylota); the head is dis-tinctly triangular and has a well-developed antennal prominence as in Chalcomyia aerea and probably the male will be found to have dichoptic eyes (holoptic in Xylota). The fourth species, both sexes, was standing in Dr. Aldrich's collection labeled "new species." The eyes of the male approach each other very closely; face concave and without tubercle in both sexes; scutellum distinctly longer than broad; metasternum pilose; body much more slender than in other species; petiole beyond first posterior cell nearly as long as discal cross-vein. The inclu-sion of these species in Chalcomyia necessitates a reconsideration of the genus. The Chilosinae and Xylotinae are intergradant and their separation is more or less arbitrarily fixed on the basis of certain characters. A number of genera, three of which concern us here, Myiolepta, Chalcomyia and Cynorhinella, occupy a rather inter-mediate position between the two subfamilies. The latter two
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