204 MEMOIRS ON THE COLEOPTERA 



cose outline, convex surface, almost obsolete dark elytral plaga and 

 by the form of the eyes and tempora; its nearest relative is the 

 smaller and less ventricose nubifer, from more southern latitudes. 

 There are before me two specimens that I fail entirely to compre- 

 hend. They are of an intense shining black throughout and, in 

 outline and striation, much resemble nubifer or temporalis. I have 

 had occasion before (Mem. Col., V, 1914, p. 299) to call attention 

 to entirely deep black specimens, in that case belonging to the genus 

 Agonoderus. Whether this condition is pathologic or not it is im- 

 possible to surmise; they were all, both Tachys and Agonoderus, 

 found unlabeled in the Levette collection, but do not appear to 

 have been stained, either by accident or otherwise. I should be 

 much interested to know whether others have observed anything 

 similar. 



Group II vittiger 

 Subgenus Isotachys nov. 



The somewhat less numerous species of this very distinct group, 

 are distinguished from those of Tachys proper primarily by the 

 position of the dorsal foveae of the elytra, which here are on or 

 attached to the inner side of the third stria; they also differ very 

 much in having the second and third joints of the antennae equal 

 in length, the sides of the prothorax less reflexed, the frontal sulci 

 less distinct and in the narrower, more parallel form of the body. 

 The base of the prothorax, instead of being generally oblique at the 

 sides as in Tachys, is here transverse usually, with the angles right; 

 but there are exceptions in both subgenera in regard to this feature. 

 The recurved part of the sutural stria is almost exactly as in the 

 true Tachys, and the posterior fovea is likewise more or less near 

 and within the hamate anterior limit of the recurvature. 



Some of the described species are not at present in my collection, 

 but such as are represented before me may be rather easily differ- 

 entiated as follows: 



Base of the prothorax transverse and straight laterally 2 



Base oblique at each side 9 



2 Color deep black, the elytra sometimes vittate 3 



Color not black 4 



3 Body elongate, parallel, moderately convex, shining, deep black, the 

 elytra each with a wide flavate vitta outside the axial line, from base 

 to apical fifth, reduced in some individuals and frequently wholly 



