200 Trans. Acad. Sci. of St. Louis. 



accidentally,— without distinct transverse impresssion; elytra well 

 developed, much wider and longer than the prothorax, the humeri 

 widely exposed but somewhat rounded, the post-scutellar impression 

 short but rather deep; abdomen slender, very much narrower than 

 the elytra and about as wide as the prothorax, the basal impressions 

 coarsely and densely punctured; legs slender, moderately long. Male 

 with a very small angular sinus, not more than a fourth or fifth as wide 

 as the segment at the apex of the sixth ventral. Length 3.0 mm. ; width 

 0.63 mm. California (Mendocino to Pomona). [= Tachyusa lin. Csy.]. 



linearis Csy. 



14_Elytra relatively broader, the humeri widely exposed at base though 

 obtusely rounded ; general form moderately convex 15 



Elytra relatively narrower, the humeri only slightly exposed; form 

 strongly convex 18 



16— Elytra large and well developed, the suture much longer than the pro- 

 thorax as usual. Form parallel, stouter than in linearis, moderately 

 shining, piceous-black, the under surface behind the third ventral 

 blackish; legs pale testaceous, the antennae piceous; pubescence 

 rather coarse and distinct, the punctures very minute and rather close- 

 set but sparser on the abdomen; head moderate, obliquely narrowed 

 behind, the neck rather more than two -thirds as wide, the vertex 

 with a rather shallow and rounded median impression; antennae 

 scarcely extending to basal two-fifths of the elytra, the first three 

 joints subequal in length, the outer joints only feebly incrassate, the 

 tenth not quite as long as wide; prothorax obviously, though not 

 greatly, wider than the head, only very slightly wider than long, the 

 sides very feebly and broadly subangulate at apical two-fifths, thence 

 distinctly converging to the well-marked basal angles, the surface 

 convex, scarcely visibly impressed along the middle posteriorly, with a 

 short feeble transverse ante- basal impression; elytra but slightly trans- 

 verse, very much wider and longer than the prothorax, the post-scut- 

 ellar impression deep and slightly elongate; abdomen widest at the 

 apex of the fourth segment, where it is distinctly narrower than the 

 elytra, the sides thence feebly converging and straight to the base, the 

 basal impressions very deep, coarsely and densely punctured, the fourth 

 tergite also impressed and coarsely punctate at base; legs rather long, 

 the first three joints of the hind tarsi rapidly decreasing in length. 

 Male with the angular sinus of the sixth ventral larger and deeper than 

 in linearis. Length 3.2 mm.; width 0.78 mm. California (Mendocino 

 Co.). [—Tachyusa exp. Csy.] . . . . = experta Csy. 



Elytra much shorter and more strongly transverse, the suture never more 



than very slightly longer than the prothorax; form sublinear 16 



16 — Prothorax not transverse, hexagonal, not wider than the head. Body 

 slender, shining, black, the three basal ventrals somewhat paler; legs 

 pale, the antennae piceous-black; punctures very fine, granuliform, 

 close-set, the pubescence fine and inconspicuous; head rounded, fully 

 as long as wide, the eyes rather small; neck but little more than half as 

 wide; vertex with a very small rounded impression; antennae gradually 

 and rather strongly incrassate, the second and third joints elongate, 

 subequal, each somewhat longer than the first, the ninth and tenth 



