142 MEMOIRS ON THE COLEOPTERA 



rapidly, arcuately converging posteriorly, the humeri well marked and 

 but slightly obtuse; punctures somewhat large and deeply impressed, 

 arranged in rather irregular series, with minute remote punctures on the 

 intervals, all the punctures bearing setae, the subsutural stria very fine, 

 not evidently punctate and only moderately flexed outward basally; 

 basal segment of the abdomen not quite as long as the next three, each of 

 which is much shorter than the fifth; broad mesosternum between the 

 coxae even, wholly devoid of carinse; tarsi slender. Length 1.8 mm.; 

 width 0.9 mm. Michigan (Detroit). 



In the single type the fine subsutural stria becomes rather broadly 

 and deeply impressed for a short distance on the upper part of the 

 apical declivity. It will be noted that lacustris differs very greatly 

 from montanus, not only in the even, minute and very remote pro- 

 notal punctulation of the latter, but in the seriate elytral punctures 

 and absence of the two carinules on the intercoxal part of the meso- 

 sternum; the deep marginal gutter of the elytra, ending just behind 

 the humeri in a fovea, is virtually similar. From duryi it differs 

 in the less rounded sides of the elytra and shorter ninth antennal 

 joint, from impressus in the very fine subsutural stria and short 

 transverse eighth antennal joint, and, from waltoni, in the appar- 

 ently shorter third and fourth antennal joints, more transverse 

 prothorax, very feeble and impunctate subsutural stria of the elytra 

 and in its somewhat smaller size. 



Symbiotes oblongus n. sp. Outline oblong, only moderately convex, 

 shining, pale yellowish-testaceous in color, the bristling pubescence as in 

 the preceding; head as usual, the antennae much longer than the head and 

 prothorax, the second joint shorter and much narrower than the first 

 and longer than the next two, third and the following subequal, quadrate, 

 closely joined, gradually increasing very slightly in size, the eighth trans- 

 verse, ninth and tenth on the flattened side as should always be assumed 

 subsimilar in outline, obtrapezoidal and slightly transverse, the eleventh 

 not as long as the two preceding, obtusely and very obliquely acuminate; 

 prothorax scarcely less than twice as wide as long, the parallel sides broadly 

 rounding and converging in about apical half, the basal groove finer than 

 in the preceding, the remaining features almost similar, except that the 

 closer punctures of the median part are not so large and are less close-set 

 or conspicuous; scutellum short, transverse; elytra unusually long, parallel 

 and feebly, very evenly arcuate at the sides, rapidly rounding and cir- 

 cularly obtuse at apex, just visibly wider than the prothorax and dis- 

 tinctly more than three times as long, the lateral gutter and subhumeral 

 fovea moderate, the humeral angles obtuse and slightly rounded; punc- 

 tures rather coarse, moderately close-set in rather even series, with a 

 few other minute scattered punctures, which become numerous and sub- 

 granose near the suture, the subsutural stria fine and shallow, stronger 

 basally, where it is strongly everted along the base to the end of the 



