of the North American Orthoptera. 477 



angulated and bent inwards in Tettix, is here rounded and 

 straighter ; the lateral carinae are not so prominent as there, 

 or so strongly bent inwards in advance of the broader por- 

 tion ; the front border is thrust forward at an angle par- 

 tially concealing the head; the prosternurn is very strongly 

 folded transversely, forming a very deep, sharp, angulated 

 groove, which in Tettix is not nearly so deep, nor are its 

 sides so nearly approximated ; wing-covers considerably 

 longer and narrower than in Tvttix. This genus further 

 differs from Tettix in that there is a small circular swollen 

 space devoid of facets, set off from the upper inner border 

 of the eye. The same is true of Batrachidea, but much 

 more indistinctly, since it cannot .be discovered without 

 the aid of such a lens as will readily separate the facets of 

 the eye. 



* 1. T. LATERALIS. 



Acrydium laterale, Say, Am. Ent. ; I. PL 5. (1824.) 



" " Say, Ent. of N. Am. (ed. Le Conte) ; 



" I. 10. PL 5, figs. 2, 3. (1859.) 



Tetrix lateralis, Harr., Cat. Ins. Mass. ; 57. (1835.) 



" Harr., Report, 3d ed. ; 187. (1862.) 



" polymorphd) var. A, Burm., Handb. d. Ent. ; II. 



659. (1838.) 



Mass., (H. Coll., Sanborn.) Maine, (Packard.) N. 

 Hampshire, (H. Coll.) Conn., (Norton.) S. Illinois, 

 (Thomas.) 



*1. T. POLYMORPHA. 



Tetrix polymorpha, var. B, Burm , Handb. d. Ent.; II. 



659. (1838.) 



Tetrix parvipennis^ Harr., Cat. Ins. Mass.; 57. (1835.) 

 " " Harr., Report. 3d ed. ; 187, fig. 82. 



(1862.) 



In this species the wings are almost abortive, and the 

 pronotum extends only to the tip of the abdomen, while 

 in T. lateralis the wings extend beyond the pronotum, 



