﻿52 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lOO 



Mesonotum dullish gray with four faint grayish vittae, which ex- 

 pand and coalesce in front of the scutellum; pile yellow and black 

 mixed. Scutellum translucent, dark, with yellowish pile, a few black 

 hairs on some specimens. Pleura dark, very lightly pollinose, the pile 

 yellow, black on the upper edge of the mesopleura. Legs black, apices 

 of the femora, basal one-third to one-half of the tibiae, and the basal 

 segment of the four front metatarsi yellowish ; pile mostly white, some 

 black hairs intermixed. Wings hyaline, the stigma black; squamae 

 yellow with slightly darker fringe, halteres yellow. 



Abdomen black, rather dull but shining on the apices of the seg- 

 ments, with three pairs of gray lunules; the first pair broadest and 

 yellowish on the sides, their inner ends almost connected ; second pair 

 connected and very narrowly reddish on the sides ; third pair similar 

 but all gray and not reaching sides. Pile mostly whitish. 



Female. — Very similar; the front wide and entirely grayish pol- 

 linose, only a small spot above the antennae shining ; ocellar triangle 

 quite large, the rear pair remote; fifth tergite with a pair of widely 

 separated gray pollinose spots. 



Holotype., male. — Umiat, Alaska, June 23, 1947 (K. L. Knight). 

 U. S. N. M. No. 58823. Allotype, female, Matanuska, Alaska, May 

 26, 1945 (J. C. Chamberlin). 



Paratypes. — Two males, Matanuska, Alaska, May 19 and 27, 1945 

 (J. C. Chamberlin) ; 1 male, Umiat, Alaska, June 26, 1947 (K. L. 

 Knight) ; 5 females, Matanuska, Alaska, May 17, 18, 19, and 22, 1945 

 (J. C. Chamberlin) ; 1 male, Umiat, Alaska, June 26, 1947 (K. L. 

 Knight) . The Matanuska specimens were all taken in a rotary trap. 



This species looks superficially like AseTnosyrphus willingi Smith, 

 but the broader stigma, more slender femora, and somewhat smaller 

 ocellar triangle place it in Helophilus. It indicates a connecting link 

 and might well be placed in either genus; it likewise indicates that 

 willingi may not be a true Asemosyrphus. 



