TUE LA5[ELT.IC0IfX BKICTLEn. 



990 



larged and projecting for^rard 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 oust of the r\lississii)pi. Of these four 

 liave been taken in Indiana, while another i)rol)a))ly occurs. 



KEY TO IXDI-VNA SPECIES OF CKEMASTOCHILfS. 



(I. Mentum plate acutely ungulate and entire behind ; legs not fossorial, 



tarsi as long as the tibiie : hind angles of thorax triangular, smooth, 



continuous with the side margin; front angles continuous with the 



disk, punctured. 1S61. knochii. 



(HI. Mentum plate distinctly notched or with a deep emargination behind. 



h. Notch on hind border of mentum plate small, acute; front angles 



prominent and distinct from the dislc ; hind angles not continuous 



with the disk. yAKioLosrs. 



bh. Notch of mentum plate wide and deep.* 



I-. Disk of thorax coaiscly and densely punctured. 

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

 continuous with the outer margin of the disk. 



1862. CANALICFLATUS. 



dd. 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. 1863. castane-i^. 

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

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



1S64. HAKBISII. 



180] (.5925). Cbemastochilus kxochii 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 not 

 wider than aijex, 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, Slarshall and Kosciusko counties; rather fre- 

 quent beneath rubbish along the beach of Lake ;\riehigan ; 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 2.5-Augnst 26, 



C. varioloswi Kirby, lenoth 9 mm., occurs in the "iliddle States 

 region," and has been recorded from Cincinnati. 



