80 Trans. Acad. Sci. of St. Louis. 
Lathrobium Grav. 
The general aspect of the numerous species of Lathrobium, 
when compared with the related genera below, is stout, com- 
pactly built and large or moderately large in size. There is 
marked uniformity in these respects, giving the species a 
habitus which enables us to generically identify them at once; 
but in many characters, even those of the gular sutures and 
antennae, there is notable variety. The contrast between the 
extremely thick antennae of armatum and related species, 
and the long slender filiform antennae of gravidulum, for 
example, is very remarkable, and, in the related genus 
Litolathra, the antennae are still longer and more slender. 
The gular sutures vary notably, from approximate and dis- 
tinctly converging posteriorly, to widely separated and 
parallel; they are always straight or very nearly so however. 
The elytra are sometimes distinctly wider and longer than the 
prothorax in both sexes, but are frequently much shorter than 
the prothorax, in which case the wings are probably more 
or less curtailed or aborted. In the armatum group, and, in 
all probability to a greater or less degree throughout the 
genus, there is very little difference in form of the body or 
relative size of the elytra in the two sexes, but, as far as 
noted, the female is a little smaller and narrower than the 
male, in opposition to a somewhat general rule. The species 
are very abundant but have never been carefully worked out, 
even in the European fauna, and have never been thoroughly 
collected in America. They are especially abundant in the 
northern Atlantic districts and appear to be somewhat local 
in habitat.* Those species represented by material in my 
cabinet may be described as follows: — 
* Of those Lathrobia not having a pleural fold on the elytra, I have col- 
lected 11 species in less than two weeks of August, on a small area of 
about 100 acres in Rhode Island, and, from Mr. F. Blanchard, have 
received 19 species taken in the immediate vicinity of Lowell, Mass. Only 
6 species are common to these series, owing perhaps to the decidedly 
warmer climate of the southern New England coast, but enough can be 
inferred from this to prove that we hardly yet begin to know the species. 
