70 PROC. ENT. SOC. WASH., VOL. 20, NO. 4, APR., 1918 



SYRPHIDAE. 



Chrysotoxum coloradensis, new species. 



This species is near laterale and pubescens. 



Mate. Head Antennae black, shorter than head. First joint slightly 

 shorter than second, third joint slightly longer than first and second 

 together; bristly hairs on first two joints, black; arista deep yellow, brown- 

 ish towards apex. Front shiny, brownish-black with numerous long 

 brown hairs and a broad band of short, yellow pubescence along the eyes. 

 Ocellar triangle shiny black, with numerous long dark hairs and a whitish 

 pubescence" across the base, front ocellus yellowish.-white, basal pair quite 

 reddish. Face pale yellow, finely pubescent and covered with numerous 

 yellowish-brown hairs, shorter than those on the front, a black stripe 

 reaching from antennae to the oral margin, very narrow at the antennae 

 and much broader at the tubercle. (Sometimes this stripe is interrupted 

 by a narrow yellow stripe between the oval margin and the facial tubercle.) 

 Cheek yellow, with a broad, shiny, black stripe reaching from the oral 

 margin to the eye. 



Thorax black, clorsum sub-opaque, Avith a bronze reflection and slightly 

 shiny along the sides; dorsum covered with numerous, yellow hairs, more 

 reddish along the sides. In tlie middle are two, faint, yellowish stripes 

 extending from half to two thirds the length of the thorax; the lateral 

 edge has a yellow stripe broadly interrupted in back of the transverse 

 suture. Pleura black, posterior half of mesopleura pale yellow, extending 

 up to the base of the wing. Scutellum yellow, brownish in center; bristly 

 hairs on basal half yellow, those on apical half, brown and slightly longer. 

 Abdomen mostly yellow. The lateral carina black on first, second and 

 third segments, yellowish-brown on fourth and fifth and yellow on apical 

 corner of all the segments except the first. First and second segments 

 black, second with a yellow, arcuate fascia across the middle, broadly in- 

 terrupted in the middle and dilated towards the outer-edge. (Extreme 

 apical edge of segments sometimes yellow.) Third segment with a narrow 

 black fascia entirely across the base and widening as it meets the carina; 

 a wider black fascia near the middle extending obliquely towards, but not 

 touching, the apical corner (the fasciae on this segment are variable in 

 width) ; segments four and five have a very narrow black fascia of uneven 

 width along the base, connecting with the carina; fourth segment lias a 

 black spot in the center and a longer one towards each apical corner; fifth 

 segment has three black spots in a triangular form. All the black mark- 

 ings on the dorsum and the yellow on the apical part of the last three seg- 

 ments covered with numerous, short, black, bristly hairs. Venter black, 

 three segments visible, basal segment with a narrow yellow fascia along 

 the apical edge, broader on the ends and sometimes interrupted in the mid- 

 dle; middle and apical segments with a yellow fascia along the apical edge, 

 broader at ends and two ovate yellow spots. Black, bristly hairs located 



