COLEOPTERA. 159 



robust, scarcely twice as wide as long ; interocular surface distinctly convex ; 

 three times as wide as the eye ; sulcations almost entirely obsolete ; inter- 

 mediate surface evenly convex, much wider than the lateral portions ; punc- 

 tures coarse, very close, shallow, evenly distributed, not coalescent but poly- 

 gon ally crowded ; ocular lines meeting at about three lengths in advance; 

 eyes small ; antennae slender, about one-third longer than the width of head, 

 basal joints black, remaindei rather dark piceous-brown, club very promi- 

 nent ; third joint tyne-third longer than the fourth, eighth much elongated, 

 shorter than the seventh and very slightly thinner, joints of club of nearly 

 equal length ; maxillary palpi long and slender, black, basal joint piceous- 

 bla.ck, third joint strongly flattened. Prothorax arcuately, evenly, and very 

 gradually widening to a point slightly behind the middle, where it is slightly 

 narrower than long ; sides thence very feebly convergent posteriorly and dis- 

 tinctly sinuate; anterior margin very slightly longer than the posterior, sub- 

 equally and feebly arcuate ; surface nearly evenly convex, very feebly swollen 

 near the basal angles ; punctures moderate in size, evenly distributed, round, 

 rather deeply impressed, separated by less than one-half their own widths, 

 interspaces convex, shining. Elytra at base much wider than the head ; 

 sides feebly divergent posteriorly, much longer than the width at base, 

 nearly straight, except toward the apical angles, where they become strongly 

 arcuate ; together roundly, strongly, and somewhat narrowly emarginate be- 

 hind ; suture slightly more than one-third longer than the pronotum ; surface 

 of each elytron longitudinally and feebly triundulate, together impressed on 

 the suture in the basal half, very coarsely punctured ; punctures round, 

 deeply impressed, nearly evenly distributed, smaller near the humeri, sepa- 

 rated by nearly their own widths ; interspaces feebly convex, shining. First 

 three abdominal segments decreasing uniformly and extremely gradually in 

 width, fourth as wide as the first, fifth much wider and longer, sixth abruptly 

 much narrower, nearly as long as wide ; pubescence increasing greatly in 

 density toward the abdominal tip ;* border obsolete, except on the first seg- 

 ment, where it is very narrow ; surface nearly cylindrical, polished, rather 

 finely and evenly punctulate ; transverse carinae tricuspid on the first and 

 second segments, very obscurely so on the remainder. Legs rather slender, 

 black ; tarsi piceous-black ; fourth joints strongly bilobed. 



Malr. — Posterior edge of the fifth ventral segment abruptly more strongly 

 arcuate in the middle, strongly and very narrowly impressed at the immediate 

 apex, impression totally disappearing at a very short distance anteriorly ; 

 sixth segment very narrowly and deeply sinuate at tip, sinus very acutely 

 rounded at the bottom, slightly deeper than wide and extending nearly the 

 entire length of the-segment ; seventh broadly, deeply, and roundly emargi- 

 nate at tip, surface narrowly carinate in the middle near the base. 



tfemale. — Sixth segment broadly and feebly angulate at the apex. Fourth 

 dorsal segment but slightly wider than the first, fifth slightly narrower than 

 the fourth, sixth much shorter ; punctuation slightly more sparse. 



Length 4.0-4.4 mm. 



White Fish Point and Marquette, Lake Superior, 4. 

 May be recognized without diiliculty, by the very singular enlarge- 

 ment of the fourth and fifth ventral segments, especially in the male. 



