AMERICAN PHILOSOPHICAL SOCIETY. 513 



at base, marginal one extending from tlie middle towards the tip ; 

 feet rufous. 



This insect varies in being of a paler color. I found it numer- 

 ous in fresh water ponds on Sullivan's Island, South Carolina. 



[A species of Copelatus afterwards described as C. 1^-striatus 

 Aube. — Lec] 



9. C. OBTUSATUS. — Black; elytra four-spotted, punctured. 

 Length three-tenths of an inch. 



Body black; head with two obsolete piceous spots on the vertex, a 

 single [100] impressed, abbreviated, frontal line each side; antennae 

 and palpi piceous ; elytra with two or three distinct series of punc- 

 tures, somewhat irregular, scattered behind, each elytron with a 

 pale, fenestrate, elongated, submarginal spot behind the middle, 

 and a sub triangular one near the tip ; feet piceous. 



Var. a. Body beneath testaceous ; frontal spots obsolete. 



This species approaches very near to fenestraUs, but differs in 

 having the series of large distinct punctures, in being not more 

 than half the size of that insect and more obtuse before. Found 

 on Mr. R. Haines's farm, German town. 



[A species of Agahus afterwards described as A. gagates Aube. 

 — Lec] 



10. C. STAGNINUS. — Oval, black, beneath rufous ; vertex with 

 two piceous spots; elytra with a submarginal whitish line be- 

 hind. 



Length less than seventh-twentieths of an inch. 



Dytiscus slagninus Melsh. Catal. 



Body oval, obtuse behind, black, beneath rufous; head with two 

 obscure piceous spots on the vertex, a single, impressed, transverse, 

 abbreviated line and point each side before; nasus and labrum 

 piceous; elytra with three dilated lines of irregular, profound, 

 rather large punctures, becoming confused at tip, an abbreviated, 

 submarginal, whitish line on each elytron, originating near the 

 middle of the tip ; tergum with a few hairs each side behind. 



[Also an Agahus, afterwards described as A. striola Aube. — 

 Lec] 



1823.] 33 



