18S2.] •^^'-' [Williston. 



black, with short white pile and thick gray pollen, leaving three darker 

 stripes, scutellum red ; abdomen yellow, the segments with narrow pos- 

 terior brownish lines. Legs reddish-yellow, the hind tibiga somewhat 

 brownish, terminal joints of tarsi fuscous, or black, hind femora a little 

 incrassate. Wings hyaline with a slightly yellowish tinge ; first posterior 

 cell briefly petiolate, the base of second posterior cell is an obtuse angle, 

 about midway between the two preceding species. Long. corp. G-7 mm. 

 One specimen, Kern county, California. 



GG. — Face more produced, obtusely tuberculate ; abdomen long (xylo- 

 tiform) ; with- scutellar, postalar, dorsopleural and mesopleural 



bristles. All the femora thickened and irregularly spinose 



ijugenianiyia Wlstn. 



EuGENiAMTiA RUFA Wlstn.. Canada Entomologist, Vol. xiv, p. 80, 

 California ! 



J. — Small cross-vein, before the middle of the discal cell. 

 2. — Antennae shorter than the head. 

 a. — Marginal cell open, 

 aa — Face tuberculate. , 



*. — Abdomen elongate, not club-shaped. 



\\\. — Black or greenish-black, with yellow or yellowish or fer- 

 ruginousinterrupled aljdominal cross-bands. 

 §.— Face black. 



H. — "Wings not longer than the abdomen; ocellar tubercle large, 

 prominent ; abdomen depressed, long, elliptical, somewhat nar- 

 rowed at the base, the lighter markings ferruginous or orange-yel- 

 low " (Schiner) *PyrophaBna. 



HH. — Wings longer than the abdomen ; ocellar tiibercle not unusually 

 large^ abdomen more slender, the cross-bands j^ellow, or greenish- 

 yellow. 



I. Anterior tibiae and metatarsi of male dilated Platycheirus. 



Plattcheikus quadratus SaJ^ Washington Territory, Kern Co., 

 California ! 



I cannot distinguish specimens from these localities from our Eastern 

 ones ; the color of the hind legs var^'^ much as they do in the East. 



? Platycheirus hypereoreus Staeger. 



Another species from Washington Territory does not differ in any note- 

 worthy degree from a female specimen of hyperboreus identified by Baron 

 Osten Sacken, but the male's tibiae are not dilated. I am strongly inclined 

 to believe that the dilatation is nothing more than a specific character, and 

 that the name Platycheirus should be given up as misleading, and all the 

 species placed under Melanostoma. P. quadratus, is variable, and only a 

 large amount of material will settle the question whether they are a group 

 of closely allied species, or merely varieties ; in the former case, the genus 

 should be retained, in the latter, it .should be united with Melanostoma. 



