332 PROCEEDINGS OF THE NATIONAL MUSEUM Vou. 1138 
pale gray scales. ‘Tibiae slightly expanded toward apices, scales sim- 
ilar to those on the femora. Tarsal claws connate for about one- 
third their length, moderately divergent. 
MeEaAsuREMENTS: The following measurements were taken from the 
type specimen (a male) of S. sparsus, the lectotype (a female) of D. 
obesus (Dietz), and a female from “Col.”” (USNM). All measure- 
ments are in millimeters; an asterisk indicates measurements taken 
only from the type specimen of S. sparsus Casey: 
Male Females 
Mean Extremes 
Body length 2.\55 3. 45 3. 20-3. 70 
Elytra length 1570 2. 30 2. 10-2. 50 
Elytra width at base 1. 05 1, 49 1. 38-1. 60 
Prothorax length 0. 65 1. 03 0. 96-1. 10 
Prothorax width 0. 75 1.14 1. 03-1. 25 
Rostrum length 1. 00 1. 69 1. 49-1. 90 
Rostrum length before 0. 50 1G. 1. 15-1. 20 
antennal insertion 
Funicular segment 2 length 0. 136* 
Funicular segment 3 length 0. 085* 
Brotocy: At present, no information is available on the biology of 
this species. 
Discussion: Except for sexual dimorphism, the types of Smicronyx 
sparsus Casey and Desmoris obesus Dietz agree so closely in external 
features it seems unlikely that they represent two distinct species. 
Therefore the name Desmoris obesus bas been placed in synonymy 
with the earlier name, Smicronyx sparsus Casey. 
This species strongly resembles S. constrictus (Say), but S. con- 
strictus has larger and more closely spaced scales and a much less 
distinct smooth median line of the prothorax than does S. sparsus. 
In addition, the antennal club is usually glabrous at the base in S. 
sparsus, but is pubescent in S. constrictus. 
DistrisutTion: The few existing records indicate that this species 
exists in the Great Plains region and the front range section of the 
southern Rocky Mountains. 
SMICRONYX FULVUS GROUP 
Description: Similar in size to the S. constrictus group. Rostra 
of both sexes almost straight; cylindrical and smooth before antennal 
insertions in female (fig. 10). Second segment of antennal funicle 
shorter than first except in S. incertus (Dietz), distinctly longer than 
third segment. Emargination of prosternum rounded. Elytra mod- 
erately convex, widest at base, humeri prominent and declivities 
distinct. Third tarsal segment much broader than first two segments. 
