68 FAMILY TT. — CABABiPiE. 



About 130 species of Bembidium are known from the United 

 States. Of these 27 have been taken in Indiana, while eleven others 

 perhaps occur. On account of this large number of species the 

 genus has, for convenience, been divided into three groups based 

 upon the position of the dorsal punctures and the form of the hu- 

 meri of the elytra. The dorsal punctures are located either upon 

 the third interval or the third stria. In two of the species, how- 

 ever, viz., Icevigatum and semi striatum, there are irregular rows of 

 small punctures upon all of the intervals. These are placed in 

 their proper sequence in the group having the "dorsal punctures on 

 third interval." The form of the humeri, whether rounded into 

 the sides of the elytra or subangulate with the latter, is also used 

 as a character of importance. The tables which follow have been 

 adapted from those given by Hayward, loc. cit., to fit the species 

 occurring in the State. 



KEY TO GROUPS OF INDIANA BEMBIDIUM. 



a. Elytra with two or more dorsal punctures on the third interval. 

 ' b. Humeri of elytra subangulate; eighth stria distinct from the margin. 



Group A. 



bb. Humeri of elytra rounded. Group C. 



aa. Elytra with two dorsal punctures on the third stria. Group B. 



Group A. 



In this group the first puncture usually occurs on the third in- 

 terval just in front of or just behind the middle, the second one- 

 third to one-fourth from apex. The humeri are more or less an- 

 gulate where they meet the sides of the elytra. It includes the In- 

 diana species of Groups I to IV of Hayward. 



KEY TO INDIANA SPECIES OF GROUP A. 



a. Elytral striae more or less abbreviated or indistinct behind the middle ; 

 mentum with a short, bifid tooth. 

 b Elytral intervals with irregular rows of sparsely placed, setse-bearing 

 punctures ; color green or bronzed. 74. icevigatum. 



bb Elytra with two dorsal punctures on the third interval; color black, 



, . . 75. NITIDUM. 



very shmmg. 



Elytral striae entire ; mentum with a large entire tooth. 

 c. Elytra with two quadrate impressions on the third interval, each en- 

 closing a dorsal puncture. 

 d. Elytra with the fourth stria sinuate. 



e Slender, elongate, convex ; thorax as long as wide, not wider at 

 base than apex. ™. injsquale. 



ee Broader, less convex ; thorax distinctly wider than long, slightly 

 wider at base than apex. littorale. 



a a. 



