THE GROUND BEETLES. 1 :'> 



thorax, emarginate at base and obliquely subtruncate at tip, the 

 stria: fine; intervals flat, the third with four to six dorsal punctures. 

 Tarsal grooves indistinct. 



KEY TO SPECIES OF GROUP I-'. 



. Thorax narrower behind, the side margins more widely refiexed to- 

 ward the base; antenna? with joints 5 to 11, paler. 



233. RUFICOBNIS. 

 mi. Thorax elongate-oval, the side margins uniformly narrow. 



ft. An tenure piceous ; size larger, 7-7.5 mm. 236. GEMELLUS. 



til). Antenna? brownish-yellow ; smaller, 5-0.5 mm. 



c. Thorax black. 234. PICIPENNIS. 



cc. Thorax brownish-yellow. 235. LUTULENTUS. 



233 (S31). PLATYNUS RUFICORNIS Lee., Agass. Lake Sup., 1850, 205. 



Elongate, slender. Head and thorax black ; elytra piceous, shining ; 

 antenna^ and legs brownish-yellow. Thorax oval, distinctly longer than 

 wide, hind angles rounded ; basal impressions broad, rather shallow. Ely- 

 iral stria- fine, not punctured; intervals flat, the third with five or six 

 small dorsal punctures, the first three on the third stria, the others on the 

 second. Length 7-8 mm. 



Frequent along the margin of Tippeeanoe Lake, Kosciusko 

 County; Lake and Posey counties ; scarce. March 26-October 21. 



*234 (834). PLATYNUS PICIPENNIS Kirby, Faun. Bor. Anier., IV, 1837, 25. 



Elongate, very slender. Head and thorax black ; antenna?, legs and 

 elytra brownish-yellow. Thorax oval, about as long as wide; margin nar- 

 row, hind angles rounded ; basal impressions narrow, shallow. Elytra 

 elongate, elliptical, the stria? of moderate depth, not punctured ; intervals 

 nearly flat, the third with four to six dorsal punctures. Length G-7 mm. 



Lake, Vigo, Posey and Kosciusko counties : frequent. January 

 1-October 17. Gregarious in winter. 



*235 (835). PLATYNUS LUTULENTUS Lee., Proc. Phil. Acad. Nat Sci., VII. 

 1854, 54. 



Elongate, very slender. Head black ; remainder of body brownish-yel- 

 low, shining. Thorax more finely margined, basal impressions smaller and 

 less distinct, and elytral stria? finer than in the preceding. Dorsal punc- 

 tures four, larger than in /m-//H'/.s',\the first two on third stria, the others 

 on second. Length 5.5-0.5 mm. 



Throughout the State; frequent. Hibernates. Sometimes at- 

 tracted by electric lights. January 21-December 23. 



236 (833). PLATYNUS GEMELLUS Lee., Bull. Brook. Ent. Soc., II, 1879, 54. 



Elongate, slender. Piceous; head and thorax often darker; epipleura. 

 legs and base of antenna? dark reddish-brown. Thorax oval, one-third 

 longer than wide, side margins very narrow, hind angles obsolete; basal 



