THK LAMHU.N'oiix BEETLES. 



larged and projecting forward so as to almost close the oral cavity, 

 its sides hanging down like two curtains, whence the generic name. 

 They usually occur beneath stones and chunks in or about ants' 

 nests. The great majority of the 21 species listed have the mentum 

 entire and pointed behind, and occur from Kansas and Nebraska 

 westward. Seven, most of which have the mentum deeply concave 

 and notched behind, occur east of the 'Mississippi. Of these Four 

 have been taken in Indiana, while another probably occurs. 



KEY TO INDIANA SPECIES OF CBEMASTOCHILUS. 



a. Mentum plate acutely ungulate and entire behind; legs not fossorial. 

 tarsi as long as the tibue ; hind angles of thorax triangular, smooth, 

 continuous with the side margin; front angles continuous with the 

 disk, punctured. 1861. KNOCHII. 



an. Mentum plate distinctly notched or with a deep emargination behind. 

 h. Notch on hind border o!' inentmn plate small, acute; front angles 

 prominent and distinct from (lie disk; hind angles not continuous 

 with the disk. VARIOI.OSI s. 



lilt. Notch of nientum plate wide and deep. 



c. IMsk of thorax coarsely and densely punctured. 



(/. Front angles of thorax continuous with the disk ; hind angles 

 continuous with the outer margin of the disk. 



1XC. CANALICULATrS. 



<ld. Front angles separated from the disk by a transverse impres- 



sion ; hind angles completely separated by a groove and de- 



pressed below the surface of the disk. ISC,.",. CASTANEJE. 



re. Disk of thorax shining, sparsely and irregularly punctured; front 



angles short, obtuse, hind angles retracted and slightly depressed. 



1S('4. IIARKISII. 



is(il (fi'.rjri). CREMASTOCHILVS KNOCHII Lee., Proc. Phil. Acad. Nat. Sci., 



1853, 231. 



Elongate-oblong. Black, feebly shining. Mentum plate flat at bottom. 

 angulate and entire behind. Thorax one-half wider than long, base imi 

 wider than apex, sides broadly curved; front angles feebly prominent, not 

 limited behind by a line; hind angles triangular, smooth, limited on inner 

 side by an oblique impression; disk moderately convex, coarsely but. not 

 densely punctured; median line evident but faint. Elytra with oval, shal- 

 low, often more or less confluent, punctures. Length 10-13 mm. 



Lake, Laporte, Marshall and Koscinsko counties; rather fre- 

 quent beneath rubbish along the beach of Lake Michigan ; only one 

 each from the other two counties, these also beneath chunks on 

 borders of lakes, one of them with a colony of small brown ants. 

 April 25- August 26. 



C. rariolos-us Kirby, length !) mm., occurs in the "Middle States 

 region," and has been recorded from Cincinnati. 



