226 MEMOIRS ON THE COLEOPTERA 



I do not think that the type above described can be the male of 

 helena, the very great differences in antennal structure, its rela- 

 tively smaller eyes and prothorax and its slightly looser punctulation 

 seeming to render this improbable, though the differences in the 

 impression of the pronotum and form of the sixth abdominal seg- 

 ment are sexual in origin, without doubt, and indicate that the type 

 of filitarsis is a male. 



Tetralina alutacea n. sp. Less fusiform and more parallel, moderately 

 convex, dark piceous-brown, the punctures everywhere extremely minute 

 and dense, the lustre dull, the legs long, piceous, the vestiture very short, 

 dense; head transverse, only about two-thirds as wide as the prothorax, 

 the eyes large, prominent as in filitarsis; antennae long, slender and sub- 

 filiform, blackish, the second joint as long as the first but more slender, 

 third distinctly shorter, fourth to sixth subequal in length, fully one-half 

 longer than wide, the tenth shorter than the ninth but fully as long as 

 wide, the gradually pointed last joint not quite as long as the two pre- 

 ceding; prothorax nearly two-fifths wider than long, formed as in the 

 two preceding species, the median line in the type broadly and feebly 

 concave in less than median third of the width, the asperities of the con- 

 cavity minute and dense but evidently less minute than those of the 

 rest of the surface; elytra distinctly transverse, parallel, only slightly 

 wider, the suture but little more than a fourth longer, than the prothorax; 

 abdomen much narrower than the elytra, subparallel, distinctly nar- 

 rowing posteriorly from about the middle, the sixth segment narrow, 

 with the truncate ventral plate projecting much beyond the dorsal in 

 the type. Length 2.3 mm.; width 0.6 mm. California (Yountville, 

 Napa Co.). 



The type of this species is also a male. Alutacea differs from 

 both helence and filitarsis in its less fusiform outline and still more 

 minute and even denser sculpture. 



Tribe OLIGOTINI 



Species all minute in size, of oval or oblong, convex form and short 

 clavate antennae, of ten joints, the tarsi 4-jointed throughout. 



Somatium Woll. 



This genus is given as a synonym of the Chilean Holobus Sol., 

 in the European catalogue of 1906, but, as I cannot verify this 

 reference at present and feel sure that our species are at least 

 Somatium, it would seem advisable to describe them under this 

 name. The genus is much more developed in America than in the 

 palaearctic fauna, and the following four are additional to the three 

 previously described by the author (Ann. N. Y. Acad., VII, p. 379): 



