242 GEO. H. HORN, M. D. 



obliterated at the base, passing the inner side of the tuberosity and slightly 

 sinuous extending very nearly to the apical margin, the inner costa more dis- 

 tinct than the middle and less prolonged at tip. Body beneath black, shining, 

 not densely punctate. Length .44 inch; 11 mm. 



The anterior tarsi of the male are moderately, the middle tarsi less 

 dilated. The posterior tibiae are slightly arcuate and at the inner 

 apical angle is a short brush of hairs behind which is a distinct hook- 

 like process arising from the inner side of the tibia and curving 

 forward. The tibial spurs are exterior to this hook. In the female 

 the tarsi are slender and the hind tibiae without the brush of hairs 

 and the hook. 



The shorter head and the insertion of the antennae so much closer 

 to the frontal margin, the similarity of the elytral apices in the sexes 

 and the peculiar hook on the hind tibia of the male, mark this and 

 the next species as very distinct from all the others in the genus in 

 our fauna. By these characters the species is abundantly distinguished 

 from trituhr.rcuJata which it resembles in a general way. 



I have seen but two specimens collected in our territory, one from 

 Hudson's Bay, the second from near Mono Lake, California, which is 

 more decidedly black. 



S. bituberosa Lee. — Form oval, very slightly oblong, black opaque, 

 sparsely clothed with very short hair. Head short, densely punctured, formed 

 as in opaca. Labrum as in opaca. Antennae with four-jointed club, more ab- 

 ruptly formed than in opaca, the terminal joint nearly as long as the preceding 

 two and conical at tip. Thorax twice as wide as long, very little narrowed in 

 front, apex truncate, sides broadly arcuate, base with median lobe truncate, on 

 each side arcuate, disc slightly more convex at middle, sides feebly flattened, 

 surface densely punctured without smooth spaces. Scutellum flat, very densely 

 punctured. Elytra as wide as the thorax and twice as long, sides moderately 

 arcuate, margin moderately reflexed, more widely near the base, apices con- 

 jointly rounded in both sexes, surface densely and coarsely punctate, each 

 puncture with a very short hair, disc flat or very slightly convex, the sides 

 declivous, surface tricostate, the outer costa stronger and terminating at the 

 moderately developed tuberosity, the middle costa feeble at base, slightly curved 

 at the tip but not attaining the apical margin, the inner costa shorter than 

 the middle. Body beneath black, not very densely punctate. Length .48 inch ; 

 12 mm. (PI. V, fig. 4). 



The sexual characters here are precisely as in opaca which it 

 otherwise greatly resembles. It is however a much broader species 

 and in form more nearly resembles insequalis. It will be observed 

 also that these two species opaca and bituherosa have the middle 

 coxae more closely appi-oximated than in any other of our species, and 

 in the former might be called rather narrowly separated. 



Occurs from northern Kansas to Wyoming and Montana. 



