NORTH AMERICAN COLEOPTERA. 
9 
distinguish it. It will be observed in abhreviatus that the sides of 
the prosternum have a well marked, fine silken pubescence, but in 
this there is no such character. 
In one of the specimens before me the elytra are paler at apex. 
While I have not seen a type of this species I am quite sure that 
the forms examined are similar to the unique described by Manner- 
heim. 
Occurs in Alaska, Oregon, Hudson’s Bay Territory and Colorado 
(rare). 
C. noctnrnus Esch.— Oblong, moderately convex, color variable, surface 
shilling and with slight aeneous lustre, sparsely pubescent; antennae feebly ser- 
rate, piceous, the basal joints often paler; head coarsely, not closely punctate, 
frontal border feebly elevated ; thorax as wide as long, slightly narrowed in 
front, sides arcuate, widest at middle, a slight sinuation in front of the hind 
angles, these feebly everted, distinctly carinate, disc moderately convex, median 
impression feeble, rarely visible in front of the middle; surface finely, sparsely 
punctate; elytra oblong, a little wider at middle than the thorax, humeri ob- 
tusely rounded, striate, striae all punctate, intervals flat, or slightly convex near 
the base, sparsely finely punctate; scutellum sparsely punctate, scarcely at all 
pubescent; body beneath paler than above, the epipleurae especially so; proster- 
num very sparsely punctate, even on the lobe, sparsely cinereo-pubescent at the 
sides, the lobe moderately prominent; propleune opaque, closely and very finely 
punctate with coarser punctures intermixed ; metasternum and abdomen with 
fine, indistinct punctures, moderately closely placed, with slightly larger punc- 
tures intermixed; legs rufo-testaceous, femora always darker. Length 4 — 5.5 
mm. ; .16 — .22 inch. 
A variable species, widely spread over the northern part of the 
continent, and with an unnecessary amount of nomenclature, the 
result of local or climatic variation. A few varieties seem to deserve 
mention. 
Var. noetvrniis Esch. — Larger in size, piceous black, with teneous 
surface lustre. The double punctuation of the abdomen scarcely 
evident, except at the sides. The hind angles of the thorax are not 
paler than the disc. Alaska, Oregon, California, Nevada. 
Var. lucidulus Mann. — Smaller than nocturnus, and with rather 
paler surface and less distinct leneous surface lustre. The hind an- 
gles of the thorax are usually paler. The punctuation of the under 
side of body is more distinct, and its double character more evident. 
Of this form fallax Mann, and vestitus Mann, are merely individual 
variations. Alaska, Hudson’s Bay, New Hampshire. 
Var. bicolor Esch.— Still smaller, the hind angles of the thorax 
and the elytra castaneous, with very feeble metallic surface lustre. 
TRANS. AM. ENT. SOC. XVIII. 
(2) 
JANUARY, 1891. 
