268 PROCEEDINGS OF THE NATIONAL MUSEUM Vou. 1138 
expanded in S. converus, and there is some difference in the shape of 
the spermathecae (see figs. 120, 149). 
Disrrisution: At present, S. convexus is known only from the type 
locality (Draper, Utah), which lies at the eastern edge of the Great 
Basin section of the basin and range province. 
SMICRONYX DISCOIDEUS GROUP 
Descrietion: Prothorax robust, quite convex dorsally, strongly 
rounded on the sides, narrowed and very slightly constricted before 
the apex; scales on all sides oriented toward the middle of the disk, 
except in S. centralis (Dietz). Elytra very convex dorsally, slightly 
broader near the middle than at the base, humeri and declivities dis- 
tinct (fig. 4). Always marked with a patch of dark scales on the disk 
of the prothorax and on the basal half of the elytra. 
Discussion: The species presently included in this group are the 
same species included by Dietz (1894). The most distinguishing 
feature of this group is the presence of the patches of dark scales on the 
prothorax and elytra. 
Map 8 gives the distribution of this group. 
Map 8.—Distribution of the specimens examined of the discoideus group of Smicronyx. 
©, S. centralis; %&, S. corpulentus; @, S. discoideus. 
