10 NORTH AMERICAN 



slightly longer than the head and prothorax together, piceous-black, club 

 slightly paler ; third joint two-thirds longer than the. fourth, fourth and fifth 

 sub-equal; joints scarcely enlarged at tips: maxillary palpi long and very 

 slender, piceous-brown, tips of first and third joints paler. Prothorax arcu- 

 ately, rapidly, and nearly evenly increasing in width to a point distinctly 

 behind the middle, where it is nearly as wide as long; sides thence very 

 feebly convergent posteriorly and somewhat feebly sinuate ; basal angles 

 rather prominent ; anterior margin much shorter than the posterior, equally 

 and very feebly arcuate ; surface very feehly and transversely impressed 

 just behind the apex, broadly and feebly tuberculate near each basal angle, 

 very convex in the middle ; pronotum narrowly margined anteriorly and 

 posteriorly : punctures very fine, distant, and extremely feeble in the middle, 

 much coarser and closer near the base. Elytra at base about equal in width 

 to the head ; sides rather feebly divergent posteriorly, very slightly longer 

 than the width at base, moderately arcuate; together broadly and moderately 

 emarginate behind ; suture fully one-half longer than the pronotum ; surface 

 broadly impressed on the suture in the basal half, also feebly impressed 

 near the humeri ; punctures moderate in size, very eveuly distributed, dis- 

 tant by slightly less than their own widths. Abdominal border strong, 

 strongly rellexed. Legs moderate in length, vrry slender, black, tarsi long 

 and slender ; first joint of the posterior slightly longer than the next two 

 together, second much longer than the third. 



Mali . — Fourth ventral segment not modified ; fifth feebly emarginate in its 

 middle third at apex, emargination evenly rounded, nearly twelve times as 

 wide as deep, contiguous surface strongly flattened, or broadly and feebly 

 impressed throughout ; sixth segment strongly sinuate at tip, sinus much 

 wider and more broadly rounded than the apices, almost semicircular, nearly 

 two and one-half times as wide as deep ; seventh segment transversely trun- 

 cate at tip, lateral spines very long and slender. 



Female. — Sixth segment obtusely produced at the immediate apex, sides 

 feebly sinuate behind ; seventh segment strongly arcuate at tip. 



Length 4.7 mm. 



Lake Superior, 7. 



The elytral spot is circular, reddish-flavate, begins slightly behind 

 the middle of each elytron, and is much nearer the exterior than the 

 interior margin. 



The above description is taken from Dr. LeConte's type, which is 

 a female. 



This species greatly resembles the European ccerulescens Gyll., but 

 differs from it in the structure of the interocular surface of the head, 

 this being relatively much narrower in the latter, which also has the 

 central convexity much wider in relation to the lateral portions. I 

 have before me only a female of ccerulescens, but in several additional 

 characters it differs from chalybens to a considerable degree. 



In the former the fifth segment is roundly and very distinctly 

 emarginate in its middle third at apex, the sixth segment is much 



