BEMBIDIIN/E 87 



Group XI semistriatum 

 Subgenus Hydriomicrus nov. 



The two known species of this group do not resemble each other 

 very closely in general habitus, but both possess a very remarkable 

 character in having a series of small setigerous punctures along the 

 middle of each of the strial intervals. The mentum tooth is rather 

 sharply triangular in both species, which are typical of two distinct 

 sections of the subgenus; they may be defined as follows: 



Body ventricose, strongly convex, polished, black, the elytra indefinitely 

 piceo-rufous apically; under surface black, the legs rufous; head 

 moderate, three-fourths as wide as the prothorax and much narrower 

 than an elytron, the sulci broad and deep, the large eyes moderately 

 prominent; antennae long, slender, blackish, pallid basally, longer 

 than the elytra, with the medial joints nearly three times as long as 

 wide; prothorax barely a third wider than long, the sides inflated 

 and strongly rounded, abruptly sinuate near the base and thence 

 straight and somewhat diverging in nearly basal fifth to the right 

 and sharp angles; surface convex, smooth, the anterior impression 

 obsolete, the base depressed; stria deep, almost entire; foveae smooth, 

 deep, oval, adjoining the rather long fine carina; margins rather nar- 

 rowly reflexed; elytra oblong, two-fifths longer than wide, fully two- 

 thirds wider than the prothorax, parallel and nearly straight at the 

 sides, which are abruptly rounded at the humeri; striae rather coarse 

 but only feebly impressed, wholly disappearing at two-fifths from 

 the apex, the seventh as distinct as the others but much shorter; 

 eighth deep, at some distance from the margin; punctures notably 

 coarse, the usual two dorsal foveae not traceable. Length (cf 9 ) 

 3.5-3.8 mm.; width 1.25-1.35 mm. Pennsylvania, Virginia and 

 North Carolina (Asheville) semistriatum Hald. 



Body elongate, subparallel, moderately convex, polished, piceous-black, 

 paler beneath, the legs rufous; elytra blackish, nubilously rufous 

 externally toward base and near the apex; head large, with very 

 moderate eyes and broad shallow sulci, three-fourths as wide as the 

 prothorax and wider than an elytron; antennae testaceous, thick but 

 filiform, not quite as long as the elytra, the medial joints scarcely 

 twice as long as wide; prothorax large, nearly three-fifths wider than 

 long, the base only two-thirds as wide as the apex; sides strongly 

 and subevenly arcuate, very oblique posteriorly, becoming briefly 

 and abruptly sinuate just before the right and sharp angles; margins 

 moderately reflexed; anterior impression distinct, the base depressed 

 and sparsely punctulate; stria incomplete; foveae small, oval, moder- 

 ately deep, the carina very short; elytra one-half longer than wide, 

 scarcely a fifth wider than the prothorax, the sides parallel and 

 broadly arcuate, somewhat gradually rounding at the humeri; striae 

 moderate, distinctly impressed, obsolete only just before the apex, 

 the seventh equally pronounced and extending behind the middle; 



