Coleopterological Notices, V. 457 



The species of Euplectus seem to be completely devoid of the 

 erect capitulate setae of the under surface of the head, so character- 

 istic of some other related genera. 



THESIASTES n. gen. 



In general organization the species of this genus resemble Euplec- 

 tus, but have the body much more minute, the head smaller and 

 especially shorter, the frontal truncature narrower, the eyes rela- 

 tively larger and more prominent, the tempera shorter and the 

 abdomen completely devoid of dorsal carinae, although deeply im- 

 pressed at the base of the first two or three segments. In spite of 

 these differences I should have probably regarded them as one of 

 the subgeneric groups of Euplectus, had it not been for the fact 

 that the male sexual modifications at the apex of the venter were 

 found to be of a completely different type. The large rhomboidal 

 tumid and carinate seventh ventral of the male in Euplectus, is 

 here replaced by the oval flat laterally enclosed pygidium so char- 

 acteristic of Ramecia, Actium, and other more or less widely sepa- 

 rated genera; this indicates a real divergence from Euplectus far 

 more pronounced than might be inferred from general organiza- 

 tion. The male sexual organs must indeed be remarkably different 

 in structure. 



Our known species are not numerous but many others will doubt- 

 less be discovered. They appear to live principally in turfy lands 

 bordering brackish water, and may be distinguished in the follow- 

 ing manner, the characters of pumilus being gathered from descrip- 

 tion, as the type is not accessible at present : — 



Size larger, 1 mm. in length, dark brown, the discal pit of the pronotum 



broader, deeper and oval fOSSUlatllS 



Size very minute, never exceeding 0.8 mm. in length ; discal sulcus narrower, 

 feebler and fusiform. 



Color pale ferruginous ; pronotum asperulate piimilUS 



Color dark piceous-brown ; pronotum sparsely but rather distinctly punc- 

 tate deMlis 



Color intense black, smooth, highly polished, with but the feeblest traces of 

 pronotal punctuation atratus 



T. atratus u. sp. — Slender, convex, polished, black throughout ; legs 



antennae and trophi testaceous ; head and prothorax sparsely extremely feebly 



and indefinitely punctate ; pubescence short, not conspicuous but not very 



sparse. Head rather small, distinctly narrower than the prothorax, wider 



Annals N. Y. Acad. Sci., VII, Nov. 1893.— 30 



