SYNOPSIS OF NORTH AMERICAN SYRPHID^. 241 



joint rather large, obliquely oval or rounded, arista naked, basal. Face 

 gently concave in profile below the antennae, with an obtuse tubercle 

 near the middle. Eyes pilose, contiguous in the male. Scutellum large, 

 yellowish, translucent, its border and the lateral borders of the thoracic 

 dorsum with macrochsetse. Abdomen not much longer than the thorax, 

 elliptical, thickly pilose. Legs slender, the hind x)air scarcely elongated. 

 Marginal cell of wings open, the third vein gently concave into the first 

 posterior cell ; anterior cross-vein near the middle of discal cell, 

 oblique. Type of genus, C. aurea (Scop.) Walker. 



TABLE OF SPECIES. 



1. — Hind borders of the second and third abdominal segments black, ojjaque; arista 

 reddish 2 



Hind borders of these segments not opaque black 4 



2. — Face in the middle with a V-shaped black spot 3 



Facial spot indistinct in outline ; front femora at base and the tip of all the tarsi 



black buccata, 9 



3. — Legs reddish-yellow dives 



All the femora brown ; tibiae likewise infuscated nigripes, <? 



4. — Facial spot V-shaped ; arista reddish nigripes, 9 



Facial spot indefinite in outline; arista black crcesus 



Chrysochlamys crcesus. 



Chri/sochlamys crcesus Osten Sacken, Western Diptera, 341. 



Habitat. — Utah (O. S.), California, Washington Territory, New Mexico ! 



9 . Length, 8 to 11'"'". Eesembles G. dives closely, but the abdomen lacks 

 the subopaque hind margins of the second and third segments ; the pile 

 of the abdomen is longer, the general form broader. The brown spot 

 on the facial tubercle is of an indefinite outline, not V-shaped as in G. 

 dives and nigripes. Antennae reddish brown, more nearly uniform in 

 color; the arista black. Abdomen uniformly of a bright bronze-green, 

 thickly beset with golden yellow pile. Legs sometimes of a wholly sat- 

 urate reddish- yellow, but the base of the femora often fuscous, or even 

 blackish. 



9 . Front with a broad polliuose cross-band, the dorsum of the thorax 

 viith more distinct pollinose stripes. 



Three males and one female (H. K. Morrison, G. F. Gaumer). 



Chrysochlamys dives. (Plate XI, figs. r>, r^a.) 



Chrjiiiochlanu/s dives Osten Sacken, West. Dipt., 341. 



Habitat. — Illinois, Missouri, Canada! Kentucky (O. S.). 

 c? , 9 . Length, 8 to 12™™. Face largely covered with ochraceous pol- 

 len, iu the middle with a large V-shaped black spot, shining; cheeks 

 shining, iu front with a narrow black stripe. Front of female shining 

 black, across the middle with a broad ochraceous pollinose band. In 

 the male the frontal triangle is black, shining above the base of the 

 antennae only, pollinose along the eyes; first and second joints of the 

 autennfe blackish above, reddish below, the third joint dark brown on 



