THE GEOUND BEETLES. 89 



a well-marked internal fold; disk usually with dorsal punctures. 

 Front tibiiV broader at tip, deeply emarginate within, the inner spur 

 situated at the summit of the notch ; hind coxas contiguous. Front 

 tarsi of males rather broadly dilated and covered beneath with small 

 scales. 



The tribe is represented in the United States by five genera, all 

 of which occur in Indiana. 



KEY TO GENERA OF PTEEOSTICHINI. 



a. Terminal joint of palpi dilated; elytra without dorsal punctures. 



XXIII. MYA.S. 



aa. Terminal joint of palpi cylindrical or slightly oval. 

 6. Front tarsi of male normally dilated. 



c. Last joint of palpi as long as or longer than the next to the last, 

 the latter with two set;i:' (bristly hairs) in front. 



XXIV. Pteeostichus. 

 cc. Last joint of palpi shorter than the next to last, the latter with 

 a number of setre in front. 

 il. Elytra with one dorsal puncture; size larger, 14 or more mm. 



XXV. BVAETHKCS. 



<U1. Elytra without dorsal punctures ; size smaller, not over 12 mm. 



XXVI. Amara. 



66. Front tarsi ot male obliquely dilated ; form oblong, subdepressecl ; 



black, very shining, usually with iridescent reflections; dorsal 



punctures one. XXVII. Loxandeus. 



XXIII. Myas Dej., 1828. 



Beetles of medium size and broad form, having the head and 

 thorax black and elytra purplish. Two species occur in the United- 

 States. Of these but one has as yet been taken in Indiana, though 

 Dury has taken the other at Cincinnati, Ohio. They may be sepa- 

 rated as follows : 



KEY TO SPECIES OP MYAS. 



((. Thorax depressed at sides; elytral stri;e punctured; length 18-20 m.n. 



120. CORACINUS. 



aa. Thorax not depressed at sides; elytral strife not or very obsoletely 

 punctured; length 13-1."> mm. cyanescens. 



120 (404). Myas coracinus Say. Trans. Amer. Phil. Soc, II, lS2;i, nO : 

 ibid. II, 482. 

 Black, elytra i)urplish. Thorax broad, transversely (piadrate, front 

 angles rounded, hind angles rectangular, margin purplish. Elyli'a broad 

 with acute strlie which are finely punctured. Length 18-20 nun. 



Throughout the State but scarce ; taken in nine widely separated 

 counties. Occurs beneath logs and chunks in open woods with a 

 loose soil. May 21-October 7. 



