10 PROCEEDINGS OF THE NATIONAL MUSEUM voi,. 68 



BRACHYCISTIS (BRACHYCISTIS) CASTANEA Cresson 



Apparently a fairly common species. Recorded from Colorado, 

 New Mexico, and Lower California. I have seen specimens from 

 Arizona, Texas, and California. The hypopygium differs slightly from 

 that of stygia as shown by the sectional drawings 46, a, h, and c. 



BRACHYCISTIS (BRACHYCISTIS) THERMARUM Bradley 



This species has the hind coxae less distinctly carinate than the 

 others in the group, and the hypopygium is rather different in some 

 particulars as shown in figure 46 and 47. 



Length, 11 5-13 mm. 



Originally described from Hot Springs, Ariz. I have seen speci- 

 mens from Higley, Mount Superstition. 



CARINATA group 



Characters. — Propodeum with one sharp or well-defined carina 

 demarcating the horizontal anterior and declivous posterior parts, 

 or there are several more or less irregular transverse carinae on the 

 upper margin of the declivous part; hind coxae rounded on postero- 

 ventral margins; second abdominal sternite more carinate; first 

 segment longer than its apical width. 



The species in this group, despite the presence of a more or less 

 obvious transverse carina on the propodeum, appear to be more 

 closely related to the atrata group than to the castanea group, judging 

 from the structure of the hypopygium (fig. 43) . 



Throughout the group the head is black, the hind coxae are not 

 carinate, and the second submarginal cell of the fore Aving is much 

 shorter than the first, readily distinguishing them from the pale 

 colored species of the castanea group. 



There appear to be three species in the group represented in my 

 material. I find very little structural variation in the large series 

 of carinata which I have examined from a single locality and were it 

 not for this fact I might be inclined to consider the specimens here 

 described as new species to be merely aberrant examples of carinata. 

 The hypopygia present no tangible differences, but this is not unusual 

 in this genus where other and striking structural distinctions 

 evidently outweigh the evidence of the hj-popygia in separating 

 species in several of the groups. 



KEY TO SPEaES 



1. Dorsum of propodeum irregularly transversal}' rugose, the division between 

 the dorsal and hind surfaces with two irregular rugae; basal segment of 



abdomen about three-fourths as wide as at apex as it is long 



rugosa, new species. 



Dorsum of propodeum without transverse rugae, finely shagreened, and with 

 a median sulcus 2. 



