180 Trans. Acad. Sci. of St. Louis. 



In the European species the abdomen is not narrowed 

 toward tip but remains perfectly parallel from base to the 

 very broad tip of the fifth tergite, and the mesosternal 

 process is not only a little narrower but also somewhat 

 shorter than in the American species, with the metasternal 

 process somewhat longer and only very narrowly rounded, 

 the cavity between the two apices being about equal in 

 length in the two species. 



Rheobioma n. gen. 



This genus is allied to Rheochara in having the three basal 

 tergites subequally impressed at base, though otherwise there 

 is but little community of facies. The prothorax, instead of 

 being very transverse and strongly narrowed from base to 

 apex, closely applied to the elytra and densely sculptured, is 

 here but feebly narrowed anteriorly, rather loosely articulated 

 and finely and sparsely punctulate, but the abdomen, espec- 

 ially, differs in its fine remote punctulation and the antennae 

 are much more elongate. The genus is wholly isolated in some 

 features of the under surface, the tip of the long slender and 

 parallel mesosternal process being separated from the meta- 

 sternum by a much longer longitudinal discontinuity than in 

 any other, and the raetasternum does not enter at all between 

 the acetabula, being merely broadly and feebly arcuate. The 

 mesosternal carina, which also seems to be a peculiar feature, 

 extends from the dilated anterior margin to a transverse line 

 through anterior third or fourth of the acetabula but is not 

 similar to the carina of Baryodma and allies, being irregular, 

 broadly flattened and very feebly elevated. Another singular 

 feature is the elongate fourth antennal joint, which is even 

 somewhat longer than the fifth and distinctly longer than 

 wide. The hind tarsi are extremely slender and evenly fili- 

 form throughout, though not quite as long as the tibiae, with 

 the basal joint almost as long as the next three combined and 

 somewhat longer than the fifth. The type may be described 

 as follows: — 



Moderately stout, subfusiform, convex, shining, pale piceous, the elytra 

 throughout rather more rufous, the abdomen blackish; antennae some- 



