DESCRIPTIONS OF ALASKAN DIPTERA OF THE FAMILY SYRPHID^. JAMES S. HINE Department of Zoology and Entomology, Ohio State University All of the species treated in this paper except Sericomia cynoctphala were collected by the Katmai Expeditions of the National Geographic Society. Full accounts of the insect collections of these expeditions are being prepared for pubhcation, but as it is desired to refer to some of the species in other papers these descriptions are published in advance of the final report. Chilosia platycera n. sp. Male and female shining black. General form of the body elongate and rather slender. Vestiture of the body mostly pale, scutellum with a marginal row of slender black bristles, eyes naked, antennse yellow, aristce dark, naked; legs largely black, apex of each femur yellow, tibiffl and tarsi partially yellow; wings pale yellowish hyaline. Length 5-7 mm. Female: Eyes bare, face and front shining black, front largely pale pilose, but with a few black hairs intermixed, face below the antennae concave, facial tubercle rather prominent, much nearer the mouth than to the base of the antennae. Antenna wholly yellow, arista dark, nearly black, bare, third segment unusually large, only slightly longer than wide. Thorax wholly shining black with short, pale, pile rather sparsely distributed. Scutellum with a few slender marginal bristles. Wings pale yellowish hyaline, halteres and squamae pale, nearly white; legs in large part black, narrow apex of each femur, base and apex of each tibia and second, third and fourth tarsal segments on all the feet yellow. Abdomen shining black all over, pilosity short and pale grayish in color. Male: Colored like the female, frontal triangle with long black pile, antennae yellow, third segment decidedly smaller than in the female, pilosity of the body rather long and conspicuous, especially along the side margins of the abdomen, abdomen entirely shining, slenderer than in the other sex. Female type, Katmai, Alaska, July, 1917. Allotype with the same data. Paratypes, 12 females and 3 males from the same locahty taken in June and July, 1917, and one female from Savanosky, Naknek Lake, Alaska, July, 1919. Type in the Ohio State University Collection. 143
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