32 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



Head hemispherical, rather large, broader than the thorax. Antennae 

 not longer than the head, varying, sometimes the first two joints very- 

 short and the third nearly round, frequently with the third joint elon- 

 gated, as also the second; arista basal, bare. Face in the sexes usually 

 different in profile, in the male generally less concave, the epistoma 

 less projecting, and sometimes with a distinct, more or less prominent 

 convexity near the middle; in the female usually deeply concave and 

 the epistoma salient. Eyes in the male contiguous (in some exotic 

 species broadly separated). Frontal triangle sometimes swollen and 

 with a distinct pit-like depression in the middle. Front in the female 

 with lateral, transverse, irregular wrinkles, in the middle usually a slen- 

 der longitudinal space, smooth, bounded on each side by a linear groove; 

 over the antennae usually with a transverse arcuate groove, below which 

 the space is smooth. Scutellum gently thinned above near its border, 

 sharp, sometimes wrinkled on its disk. Abdomen short, oval, flattened, 

 the borders, however, rounded, not thinned. Legs moderately strong, 

 simple, the hind femora scarcely longer or thicker than the others. 

 Marginal cell of wings open, third vein straight, anterior cross-vein con- 

 siderably before the middle of the discal cell, rectangular, the last sec- 

 tion of the fourth vein frequently more or less bent, always joining the 

 third vein considerably before its tip, often bent in so that the tip is less 

 remote from the anterior cross- vein than is the posterior angle of the cell 

 which it closes ; the cross- vein at outer end of discal cell also joins the 

 fourth vein considerably before its angle, the false vein frequently en- 

 tirely wanting, never very distinct. 



My reasons for uniting Orthoneura with this genus are explicitly 

 enough given by Loew (Stett. Ent. Zeit., 1843). It is true this author 

 and Schiner did afterwards make use of Orthoneura, but that the former 

 did not have a very clear idea of the genus is sufficiently shown by his 

 G. nigripes, described in the male as Chrysogaster and in the female as 

 Orthoneura iistulata. The character these authors used was the manner 

 of termination of the fourth vein. 



TABLE OF SPECIES. 



1. — Base and tip of tibiae, or at least first two joints of tarsi, yellow or yellowish red; 

 last section of fourth longitudinal vein rectangular; anteunte elongate . 2 



Legs wholly black ; last section of fourth vein curved or bent 5 



2.— The last section of the fourth vein joins the third beyond the tip of second vein, 

 rectangular, with a stump of a vein in the middle; second joint of antennae 



nearly as long as the third ; eyes with linear markings nitida 



The last section of fourth vein joins the third opposite or before the tip of the sec- 

 ond ; disk of abdomen opaque 3 



3. — Eyes with linear markings bellula 



Eyes unicolorous 4 



4. — Abdomen broadly oval ; wings with brownish cloads pictipennia 



Cross veins of wings not clouded pulchella 



