60 



This species is remarkable because of its structure, color of the 

 pile and villous wings. Most of the species in the genus have the 

 villi more or less apparent, but they are always grayish, not as 

 stout as, and usually decidedly longer than in this species. The 

 insect is quite typical of Cyrtopogon except for its narrow ab- 

 domen, in which it approaches Lasiopogon, but it is more tapering 

 and the genitalia not as large and conspicuous, and the pile is 

 very much more abundant. It forms a good connection between 

 the two genera, which are really only feebly separated. 



Syrphidae. 



Only one species of Chamaesyrphus has been previously recog- 

 nized from North America and the new species here described is of 

 unusual interest because it is somewhat intermediate between the 

 genera Pelecocera and Chamaesyrphus, but shows greater affinities 

 to the latter. The third antennal joint is very large, less rounded 

 than in Chamaesyrphus willistoni and less angular than in Peleco- 

 cera, the arista dorso-terminal. The two genera have appeared 

 abundantly distinct but it is possible that further knowledge of 

 the species comprising them may once more lead to their unison. 

 The two North American species of Chamaesyrphus may be sepa- 

 rated by the following table. 



Arista dorso-terminal, the third antennal joint with broadly rounded apical 



corners, the sides and apex slightly convex; joint widest apically 



apichaetus, n. sp. 



Arista situated slightly before the middle of the third antennal joint; third joint 

 orbicular willistoni Snow. 



Chamaesyrphus apichaetus, new species. 



Superficially similar to Chamaesyrphus willistoni, but differing as explained in 



table, and otherwise. 



Female. — Length, 5 mm. Face and front shining black, the former densely 

 whitish-pollinose except a large sub-cordate spot about the small but prominent 

 tubercle, and most of the cheeks, which are of a brownish ground color. In 

 profile the face is moderately concave above, retreating below the tubercle, but 

 the lower third of the face is prominent, so that the tubercle is not wholly re- 

 sponsible for the prominence here. Pile whitish, limited to the side margins 

 and cheeks. Sides of the front below, and a broad band on the lower third, 

 narrowly separated from the base of the antennae by a shining area, thinly 

 yellowish-pollinose. Pile rather short, not very abundant, black. Occiput 

 shining black, the orbits grayish pollinose; pile black above, pallidly yellowish 

 below. First antennal joint very short, black; second a little longer than broad, 

 slightly tapering, its apex broadly rounded, piceous or brownish red in color; 

 third joint very large, broadest apically, its corners broadly rounded, its mar- 

 gins a little convex, reddish in color, its upper and apical margins narrowly 

 brown. Arista black, situated on dorso-apical corner, as long as the antennae, 

 straight, not robust, tapering. 



Thorax greenish black; pleura and sides of mesonotum thinly whitish-polli- 

 nose, the latter dorsally with thin yellowish pollen; on the anterior two-thirds, 

 when viewed from behind, with a yellowish pollinose geminate median stripe. 

 Pile of mesonotum short, black; on the lateral and posterior margins and on the 

 pleura, short, white. Scutellum greenish black, pale pilose, with four bristles. 



