522 PROCEEDINGS OF THE ACADEMY OF 



of elytral punctures distinct and regular, extending to the base ; outer hind 

 claw less than one-half as long as the inner one. Dacotah. 8. sinuatus. 



b. Body slightly convex, elytra coarsely reticulated, anterior and middle 

 tarsi strongly dilated : Meladema Lap. 



63. Elongate oval, black, thorax nearly three times as wide as long, sides 

 nearly parallel behind, rounded in front ; elytra a little wider than the thorax, 

 and forming an angle with it. Lake Superior and Saskatchewan. Agabus 

 ang. Lee. . . . . . . . . . 9. angustus. 



B. Claws of hind tarsi very unequal. 



A. Anterior and middle tarsi with three joints strongly dilated, and furnished 



with small cups beneath ; 



a. Elytra with numerous impressed transverse lines, Cymatopterus Esch. 



* Legs black : 



Sides of the thorax sinuous near the anterior angles, which are 



subacuminate. 



75. Elongate, gradually narrowed at each end, but less obtusely behind, 

 black, nearly oyjake ; head and thorax finely sculptured, lines of elytra fine 

 and approximate ; front and base of antennae obscure red. Kadjak. 



10. obscuratus Mann. 



Sides of thorax rounded ; anterior angles acute. 



74. Elongate oval, very slightly dilated behind the middle, above piceous, 

 shining ; sides of elytra, basal margin and suture anteriorly pale, transverse 

 lines fine approximate; thorax pale piceous, with a large transverse dark 

 cloud, sculpture fine and dense, head dark brown, front base of antennae and 

 two spots between the eyes pale ; beneath very black. Saskatchewan. 



11. seminiger Zee. 



64 *70. Elongate oval, shining, elytra cinereous brown, sides and basal 

 margin pale, transverse striae fine, but less dense than in the preceding ; 

 thorax black, with the sides and an interrupted transverse band pale brown, 

 sculpture dense ; head black, with two vertical spots, front labrum and base 

 of antennae pale ; beneath very black. Lake Superior and Methy. 



12. longulus Lee. 



** Legs brown or pale piceous ; color above brown, shining, sometimes dark, 

 sometimes pale ; thorax with a dark transverse cloud ; 



Sides of thorax broadly rounded, or nearly straight. 



62. Elongate oval ; thorax with sinuous rugosities, not connected together ; 

 lines of elytra deep and distant ; legs very dark. San Diego, California 9 



13. strigosus Lee. 

 62. Elongate oval ; thorax with very deep, dense and anastomosing rugosi- 

 ties ; lines of elytra deep and approximate ; legs pale. Methy 9 . 



14. exaratus Lee. 

 63. Elongate oval ; thorax with finer anastomosing rugosities, deeper in 9 

 than $ ; lines of elytra deep, moderately approximate ; front and middle 

 legs paler than hind legs. Middle States <~^ 9- Col. triseriatus Kirby. 



15. sculptilis Harris. 

 N -64. Elongate oval, slightly dilated behind ; thorax with fine, somewhat 

 anastomosing, but not very dense rugosities ; lines of elytra deep and approx- 

 imate ; legs pale, thighs somewhat darker than the tibiae. Oregon ^ . 



16. d e n s u s Lee. 



62. Elongate oval, slightly dilated behind ; thorax with fine and dense 



anastomosing rugosities ; lines of elytra very deep and approximate ; legs 



[Dec, 



