THE GROUND BEETLES. 



133 



Throughout the State; common. Hibernates. Gregarious in 

 cold weather. January 1-November 24. 



P. crenulatus Lee., 5.5-6 mm. in length, is a member of the 

 Austroriparian fauna, which may occur in the southern counties. 



*227 (821). Platynus bogemanni Gyll., Ins. Suec., Ill, 1810, 697; obso- 

 lete Say, II. 481, 



Elongate, slender. Black or piceous, shining. Thorax heart-shaped, 

 wider before the middle, rounded to a narrow base. Elytra oblong, twice 

 as wide as thorax, stria? very fine or obsolete, not punctured ; third inter- 

 val with three very small dorsal punctures. Length 5.5-6.5 mm. 



Lake, Putnam and Vigo counties ; scarce. Hibernates. Janu- 

 ary 14- July 28. 



Group E. 



A small group of winged species in which the thorax is rounded 

 oval or slightly eordiform, narrowiy margined, hind angles obtuse 

 or rounded, basal impressions usually deep and punctiform; elytra 

 nearly or quite twice as wide as thorax, with punctured stria? and 

 three (rarely four) dorsal punctures placed along the middle of 

 the third interval. 



KEY TO SPECIES OF GROUP E. 



a. Tarsal grooves present. 



b. Piceous bronze: stria? of elytra very fine; tarsal grooves on first 



j° int 228. .ERUGINOSUS. 



M). Black, legs brown; stria? feebly punctured; tarsal grooves on first 

 and second joints. 232. punctiformis. 



da. Tarsal grooves wanting. 



c. Black or dark reddish-brown ; base of antennas palpi, legs and sides 



of elytra brownish-yellow. 229. limbatus. 



cc. Black, legs reddish-yellow or reddish-brown. 



d. Elytral stria? coarsely punctured; larger, 7.5-8 mm. 



230. CRENISTRIATUS. 



dd. Elytral stria? finely punctured; smaller, 6.2-7 mm. 



231. RUBRIPES. 



*228 (824). Platynus ^ruginosus Dej., Spec. Ill, 1827. 168. 



Elongate, very slender. Head and thorax piceous ; antenna?, elytra and 

 legs dark brown, bronzed, shining. Thorax oval, convex, very narrowly 

 margined: basal impressions very small or obsolete. Elytra oval, convex, 

 emarginate at base ; stria? finely punctate : intervals flat. Length 5.5-6 mm. 



Throughout the State; common. Occurs in damp localities. 

 Hibernates. April 3-December 18. 



229 (825). Platynus limbatts Say. Trans. Ainer. Phil. Soc. II. 1823. 49: 

 ibid. II. 473. 



Elongate, rather robust. Color as given in key. Thorax subrotund. 

 margin very narrow, hind angles wholly rounded ; basal impressions small, 



