80 Trans. Acad. Set. of St. Louis. 



Lathrobium Grav. 



The o-eneral aspect of the numerous species of Lathrohium^ 

 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. 



