28 Trans. Acad. Sci. of St. Louis. 



Aderobium n. gen. — The structure of the basal parts of 

 the head, short basal joint of the antennae and type of ely- 

 tral sculpture, isolate this genus completely; it is founded 

 upon the Amazonian Cryptobium angusiifrons, of Sharp. 



Homoeotarsus Hochh. — The remarkable structure of the 

 antennal joints and absence of any well-defined beading of 

 the elytral suture, as well as some minor structural features, 

 such as the form of the mentum, will readily serve to sepa- 

 rate this genus from Hesperobium , which it strikingly resem- 

 bles in facies and general organization. The type is H. 

 chaudoiri Hoch., a male of which from Lenkoran is before 

 me. The sexual characters are peculiar, the fifth ventral being 

 feebly impressed in the middle and with a very abruptly formed 

 median emargination at the transversely rectilinear apex, the 

 emargination almost exactly circular in form, the opening being 

 narrower than its Greatest width ; the emargination of the sixth 

 ventral is somewhat as in our Hesperobium cinctum Say. It 

 has been stated that the genus Spirosoma Mots. — Bull. Mosc 

 1858, p. 206 — described from India, is the same as Homoeo- 

 tarsus, but the statement that the tarsi are one-half shorter 

 than the tibiae, with the first four joints triangular and 

 equal, the last as long as the two preceding combined, would 

 seem to indicate generic difference, for even if the tarsus 

 referred to be the anterior, it would not be true of Homoeo- 

 tarsus, where the basal joint is still notably longer than the 

 second. It is also said of Spirosoma that the second and third 

 antennal joints are equal in length, the fourth shorter, 

 whereas in Homoeotarsus the second joint is much shorter 

 than the third and equal to the fourth. 



Eucryptixa n. gen. — This genus is founded upon the 

 Amazonian Cryptobium opacum, of Sharp, and is described 

 above from a single headless specimen. As the peculiarities 

 of the elytra, referred to in the description, are of generic 

 value, this mutilation is not so important, but the cephalic 

 characters are doubtless also distinctive. There is no trace 

 of the sutural beading and juxta-sutural impressions so char- 

 ateristic of Hesperobium. 



Pycnocrypta n. gen. — The type of this genus is one of 



