214 MEMOIRS ON THE COLEOPTERA 



joint nearly four times as long as wide, the second long but evidently 

 shorter, constricted basally, longer than the next two, third one-half 

 longer than wide, constricted basally, fourth wider than long, four and 

 following very gradually and moderately incrassate, the tenth nearly 

 twice as wide as long, the last obtusely ogival, not as long as the two 

 preceding; prothorax slightly wider than long, notably convex, widest 

 at anterior third, the sides broadly rounded, strongly converging and 

 straight basally to the obtuse and blunt angles, the median line finely 

 and feebly impressed throughout; elytra short, with nearly straight and 

 very strongly diverging sides, at base rather wider than the base, at 

 apex somewhat wider than any part, of the prothorax, the suture but 

 little more than half as long as the latter and very much shorter than 

 the flanks, which project posteriorly beyond the median parts; abdomen 

 subparallel, with straight sides, about as wide as the elytra, the fifth 

 tergite perhaps a little wider than the base, a third longer than the 

 fourth. Length 2.2 mm.; width 0.48 mm. British Columbia (Metla- 

 katla), Keen. 



Much larger and stouter than maritima and less stout than 

 fletcheri, with shorter, more rapidly incrassate antennae distally, 

 much less punctate abdomen, more diverging sides of the elytra 

 and different coloration among many other discordancies. 



Thinusa nigra n. sp. Smaller, less elongate and more depressed, black 

 throughout above, piceous beneath anteriorly, the legs pale brown; 

 surface dull, the abdomen but feebly shining; punctures dense but 

 obscure, more distinct on the abdomen though still rather close through- 

 out; pubescence silvery, notably short, very stiff, not bristling, streaming 

 outward from the median line on the pronotum, much longer and bristling 

 on the abdomen; head nearly as in divergent but only four-fifths as wide 

 as the prothorax, the eyes not quite so large, the antennae similar but a 

 little shorter, blackish, paler basally; prothorax nearly as in the preceding 

 but relatively larger, very slightly more transverse and less convex, the 

 median line more strongly and less finely, though acutely, impressed; 

 elytra short, much more parallel, the sides barely perceptibly diverging, 

 at base slightly wider than the base, at apex much narrower than the 

 widest part, of the prothorax, the suture three-fifths as long as the 

 latter and but very little shorter than the sides; abdomen parallel, equal 

 in width to the eytra, the fifth tergite scarcely as wide as the base, 

 nearly one-half longer than the fourth. Length 1.7 mm.; width 0.45 

 mm. British Columbia (Metlakatla), Keen. 



To be known from divergens by its shorter and more compact, 

 more parallel build, shorter pubescence, more depressed surface, 

 darker coloration, denser punctuation throughout, and especially 

 on the abdomen, and in its more parallel elytra. 



The following may be regarded as a subspecies of fletcheri: 



