( 50 ) 
triangular yellow spot, on the lateral margin of each seg- 
ment : thighs testaceous ; tibice & tarsi somewhat darker. 
Length under one fifth of an inch. 
Allied to A. brunneus^ Nob. but the segments of the 
tergum are not margined around by dusky ; on each is a 
dusky triangle, much dilated on the posterior margin so as 
nearly to reach the lateral edge. 
OMALIUM, Grav. 
1, 0,margmatus^ Piceous, jumctured ; antennae & feet 
dull rufous. 
Inhab. Upper Missouri. 
Body oblong oval, piceous, punctured ; head^ punctures 
sparse, obsolete at tip; with an indentation each side 
between the antennae & a longitudinal impressed line each 
side at base: antennm rufous at base, red^brown-obscure at 
tip with cinereous hair : palpi rufous : thorax transverse 
subqiiadrate, punctures not crouded ; posterior edge obscu- 
rely piceous ; elytra longitudinally quadrate, coveiing 
more than half of the tergum, exterior margin piceous 
iow’ards the humerus: exterior hind angles rounded, 
sutural ones acute ; almost to be traced into striic: fed 
piceous, paler towards the tip ; tergum obscurely rufous on 
the margin, & on the posterior margins of the segments. 
Length one tenth of an inch. 
1 obtained this insect when with Major Long’s expedi- 
tion to the Rocky mountains ; I think it occurred at 
Engineer cantonment on the Missouri. 
2. O. Totundicolle^ Piceous black ; thorax rounded be- 
hind, emarginate before. 
Inhab. Pemisylvania. 
^ 0 % with rather large, numerous & profound punc- 
tures; antennm piceous, brown, the three basal joints, 
labram hpalpihonej yellow: thorax transverse oval, deeply 
emarginate before, equally punctured ; posterior angles 
rounded ; edges piceous : elytra equally punctured, long ; 
terminal edge piceous : tergum piceous, rather paler on 
NOTE. 
Oince ths orGccdinp' pa^^ns woro printed I have received the second edition of 
ihe Rcgne Anirnale (Ainer. Ed.) 
