AMERICAN COLEOPTERA. 407 



species ODly one has a smooth female, and in America only three 

 species have sulcate female and these have also smooth forms. D. 

 hybridus is a very curious Cybister-like form. 



Claws equal in hoth sexes, four anterior tarsi in the male dilated 

 into a patella with two large and numerous small cupulae ; thorax not 

 margined, laciniae of the metasternum broad, sub-triangular not reach- 

 ing the margin, posterior tibial spurs unequal, apical angle of femora 

 ciliate, coxal plates reaching the metasternum. 



D. Hnrrisii. Kirby, Fauna, p. 76. — Broadly oval, almost dilated} fulvous 

 yellow, above brown, thorax and elytra margined with yellow, the sub-apical 

 fascia well marked, transverse; underside yellow; the sutures and margins of 

 segments broadly black; coxal plates rounded. L. 1-50— 1*55 inch. 



Pennsylvania, Kansas, Lake Superior, Vancouvers. 9 , elytra 

 smooth. 



Closely allied to D. latissimus, but the elytra are less dilated at the 

 margin and the females smooth. Thomson has made this the type of 

 his genus Dytiseus, characterized by the hardly emarginate labruni ; 

 the other species form his genus Macrodytes. 



I>. latissimus, Fauna Suec. No. 768. — Very distinct by the broadly dilated 

 elytra. Dr. Sharp writes me word that he has just had % 9 of this species 

 sent him from Canada. I am inclined, however, to think that its occurence 

 will prove to have been accidental. 



D.C onfluens, Say, Am. Trans, iv., 440; dljfinis, Lee. Lake Sup., p. 212.— 

 Sli"' 'ly obovate, fulvous, head, thorax and elytra brown shot with green; 

 head • ith the clypeus and a triangular mark between the eyes fulvous; thorax 

 ti-a. .= verse angles produced, acute, margin pretty broadly yellow and bordered 

 with deeper punctures; elytra very sparingly punctulate, with three rows of 

 deeper punctures, the margin rather broadly yellowish, acuminate before the 

 apex, and emitting an irregular sub-apical fascia; underside with the margins 

 of the segments and apex of metasternum more or less black; coxal plates acu- 

 minate. L. 1-20— 1-40 inch. 



9 elytra sulcate to beyond the middle; the external costa united with the 

 seventh. 



9 var., elytra smooth. 



Kansas, Lake Superior, Russian America. 



D. parvu/us (Motsch. Et. Ent., 1852, p. 77) is not distinct from this 

 species in my opinion, from which it differs only in its smaller size- 

 It resembles D. marginalia precisely in external form and coloring, 

 but the coxal plates are formed as in D. circumcinctus. 



