40 GEO. n. HORN. M. D. 



its general aspect more depressed than any other of our species. 

 Length .14 inch ; 3.5 mm. 

 Abundant in the waters of Pennsylvania. 



S. bicarinatus, Lee. Proc. Acad. 1852, 44. 



Form elongate, elytra distinctly wider behind the middle. Thorax 

 parallel in front, then slightly rounded, becoming wider, then parallel 

 to base ; hind angles rectangular; dorsal channel and an oblique groove 

 on each side distinct. Second interval distinctly but feebly carinate 

 at base, lateral carina not prominent; disc of elytra moderately convex, 

 with distinct striae, which are deeply punctured at base, becoming 

 gradually more faint towards apex. The luteous stripe is distinct but 

 not pale. Length .14 — .10 inch; 3.5 — 4 mm. 



Occurs in Ohio. 



S. quadrimacolatus, n. sp. 



Similar in form to crenatus but diflFering as follows : — Thorax more 

 elongate, sides less rounded. Elytra more convex in both directions; 

 second interval with a short basal carina, lateral carina very feeble ; 

 disc with striae of very large deep punctures, less strong at apex but 

 not evanescent. Humeri with a rounded red spot and a short sub-api- 

 cal stripe. Legs black, apex and base of tibiae, tarsi, and antennae fer- 

 ruginous. Length .14 inch; 3.5 mm. 



At the middle of the base of the thorax on each side of the scutel- 

 lum are two small, smooth, puncture like spots, these are seen also in 

 the next species. The lateral tubercles of the thorax between the dor- 

 sal channel and the margin are here very distinct, and in the space en- 

 closed between them and the channel is a rather deep impression. In 

 form this is the most robust of our species and, with the exception of 

 linearlA, has the lateral carina of the elytra least distinct. 



One specimen. Vermont. 



S. vittipennis, Zimm. Trans. Am. Ent. Soc. 1869, 259. 



Resembles biairinatns but is less convex. The thorax is similar 

 but the hinder two-thirds are rounded in place of being parallel, the 

 hind angles are consequently less rectangular. The oblique groove 

 described in hicariiiafus is also quite evident here. In some specimens 

 the stripes are (|uite dark, and scarcely evident, in others bright add- 

 ing to the beauty of the insect. With the exception of linearis is our 

 most elongate species. Length .14 inch ; 3.5 mm. 



Illinois, South Carolina and Texas. 



