16 
NORTH AMERICAN THROSCIDAE 
feebly serrate; ninth triangular, outer angle strongly and narrowly produced, 
the anterior or apical side next to the tenth joint beingdeeply sinuate or emargi- 
nate; tenth joint with the inner side or axial length equal to the same side of 
the ninth, slightly sinuate, obliquely produced laterally, the anterior side 
deeply sinuate; eleventh joint strongly laterally produced, narrowly acute at 
point of attachment to tenth, gradually wider externally, the proximal side at 
first nearly straight then broadly arcuate to the somewhat acute apex, distal 
side straight, widest a little beyond the middle and about three times as long 
as wide. The sinuation of the distal sides of the ninth and tenth joints is deep 
and the proximal sides of joints ten and eleven are broadly arcuate, so that 
when the joints are closely applied there are large openings between. An- 
tennae of female not seen. Thorax transverse, a little more than one and one- 
half times as wide at base as long; in the male wader than the base of the elytra 
w'ith hind angles explanate and punctate, parallel at sides, thence arcuate and 
feebly sinuate and oblique to anterior angles, w'ider in front in the male than 
in the female. In the female the sides of the thorax are rather broadly arcuate 
from base to apex, a feeble sinuosity behind the middle, hind angles not 
explanate; carinae not evident in either sex, strongly bi-impressed at base; 
punctuation of pronotum rather coarser in female. Elytra slightly, obliquely 
impressed behind the humeri, sides a little rounded, scarcely narrowed, obtuse 
at apex, in male a little less rounded and apex less obtuse; striae stronger in 
the female, with rather close, subelongate punctures larger than those of the 
intervals which are rather small and close, irregularly double or even triple 
on the second, third and fifth intervals, the irregular punctuation reaching 
farther than usual posteriorly; sutural and outer intervals uniseriately punc- 
tate. Last abdominal segment not projecting beyond the elytra. Proster- 
num flat in male, rather sparsely and finely punctate, striae nearly entire, sides 
of body moderately punctate, the metasternum at middle very sparsely and 
finely so, the metasternum largely covered wfith long, soft pubescence. In the 
female the prosternum is somewhat convex and more coarsely punctate, sides 
of prothorax and metasternum more coarsely and the abdomen also more 
closely punctate. Length 3 mm. 
One pair of nearly equal size from Fredericksburg, Virginia 
(W. D. RicTiardson). 
The male may be easily distinguished by the characters given; 
the female looks much like a large female constrictor or a smaller 
female punctatus, from the former (of which I have seen none 
quite so large) it may be known by the elytra less constricted 
and not narrowed behind and more obtuse at apex, and the more 
numerous punctures of the intervals and the coarser and closer 
punctuation of the abdomen. The larger females of punctatus 
will be easily recognized, but owing to the variability of the punc- 
tuation in this species I am led to fear some difficulty in always 
placing the female of calocerus, if the specimen above described is 
the true female. It might be mentioned that this female was 
