NORTH AMERICAN COLEOPTERA. 
Group ABBREVIATUS. 
Prosternal sutures straight, nearly parallel. Maxillary palpi 
moderate in length, the last joint triangular, truncate at apex. Legs 
not long, tibiie not spinulose externally, terminal spurs small. Thorax 
with median line more or less impressed, the basal incisures feebly 
distinct, hind angles, at most, but little everted, the carina not long. 
Surface pubescent. Body winged. 
The group here defined is with difficulty separated by description 
from the one preceding, but the more convex form, pubescent sur- 
face and less prominent hind angles seem sufficient. 
The species composing the group occur in the Arctic regions of 
both continents, extending southward in the more northern jiortions 
of the temperate region, and along the mountain ranges in the 
higher altitudes still more to the south. 
In consequence of the wide distribution of the species and the 
varied climatic influences to which they are subjected, a great amount 
of variation has been produced. This range of distribution is from 
Labrador on the east to northern California on the west, and in the 
centre of the continent extending southward along the Rocky Moun- 
tains to New Mexico, thence northward in every part of British 
America to the extreme of the Alaskan peninsula. 
In the great quantity of material examined I have not been able 
to separate more than three species : 
Scutellura conspicuously clothed with pale pubescence, that of the elytra some- 
what scale like. 
Thorax narrowed in front in its apical two-thirds, sides often obtusely suban- 
gulate in front of the angular sinuation ; elytra with a denser spot of 
pubescence near the apex abbreTiatiis. 
Thorax arcuate near the apex only, the sides thence nearly straight ; elytra 
without spot of denser pubescence near tip impressicollis. 
Scutellum sparsely punctate and smooth, with scarcely any pubescence ; surface 
simply sparsely pubescent; thorax usually very sparsely punctate, the 
median impression very indistinct lioctiirniis. 
C. abbreviatus Say. — Oblong, moderately convex, piceous, with greenish 
bronze surface lustre, sparsely clothed with yellowish cinereous pubescence, 
somewhat scaly in appearance, forming a conspicuous elongate space on the ely- 
tral declivity ; anteun® feebly serrate, either entirely piceous, or with the basal 
joints paler; head coarsely not closely punctate, the frontal margin scarcely 
distinct from the clypeal ; thorax slightly broader than long, narrowed in front, 
sides scarcely arcuate, but obtusely subangulate behind the middle, then sinuate 
in front of the hind angles, these acute but not slender, scarcely divergent, cari- 
nate ; disc convex, with a median impression usually extending from base to 
apex and deeper behind, ba.sal incisures feeble, surface shining, moderately 
