GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 407 



the middle ; the sides of these segments and of the one next in front 

 have a very black line, which is interrupted at the incisures, (sometimes 

 this line runs along the whole length of the venter, continuous with that 

 on the metapleura;) the apical segment more or less yellow each side; 

 the lateral margins yellowish, and the submargin with short, black, re- 

 mote lines, and with similar oblique ones, lower down, on the sides of 

 three or lour basal segments; male. The female is paler, with the mid- 

 dle joints of the anteuna3 pale rufous, excepting at base and tip, with 

 the venter pale testaceous, and the base and a lateral, broad, and an- 

 other narrower vitta, blackish. 



Length to tip of venter, 4-5 millimeters. Width across the humeri, 

 1^ millimeters. Brought from Colorado ; it inhabits also Dakota and 

 Canada. 



The pronotum is about one-fifth wider than long, and the metapleura 

 is very remotely, shallowly punctured, and often rufo-flavous, particu- 

 larly in the females. 



OpMhalmicus, Schill. 



0. piceus, Say, (Heteropt., New Harmony, p. 18, No. 1.) — Obtained in 

 Colorado ; but is quite a common insect in the Atlantic region. 



Umhlethis, Fieb. 



U. arenarius, Linn., (Fauna Suecica, p. 955.) — Obtained at Cheyenne, 

 in August. The specimens from our Western Territories seem to cor- 

 respond very closely with those of Europe. 



Bhyparochromus, Curtis. 



E. fallax. Say, (Heteropt., New Harmony, p. 17, No. 6.) — Brought 

 from Colorado and Montana ; but quite common in Illinois, New Eng- 

 land, Canada, British Columbia, and even in California. 



Plociomerus, Amyot et Serv. 



P. diffusus, JJh\er, (Ptog. Boston Soc. Nat. Hist, 1871, p. 9.)— Col- 

 lected in Colorado. It is widely diffused in the Western United States, 

 and extends as far east as Maryland. 



Serceus, Stal. 



S. insignis. New species. — Similar in form to Araphe Carolina, H. 

 Schf. Shining black, or with the head, thorax, and legs pale rufo-piceous. 

 Anterior lobe of the pronotum A^ery high and convex. Head longer 

 than wide, subconical, very convex above, minutely granulated, pubes- 

 cent, and with a few erect, long hairs. Eostrnm extending upon the 

 intermediate coxse, piceo-rufous, with the third and fourth joints 

 blackish piceous. Antennae fulvous, or rufo-flavous; the fourth joint 

 and apex of the third blackish, these two subequal in length; the 

 second joint much the longest ; the basal one extending a little beyond 

 the tip of the tylus, armed beneath with a few long bristly hairs. Pro- 

 notum polished, the anterior lobe almost sphsero-convex, very minutely 

 scabrous, and with a few erect long hairs; against the collumis a trans- 

 verse, impressed, punctured line ; the posterior lobe abruptly slanting 

 anteriorly, remotely, coarsely punctured with black on a pale piceous 



