186 ORTHOPTEKA. 



I. Antennce U-jointed; eyes very prominent, with a project- 

 ing ridge between them, formed by a horizontal extension of the 

 flat top of the head; thorax prolonged beyond the extremity of 

 the body. 



1. Tetrix ornata. Ornamented Grouse-locust. 



Dark ash-colored ; a large white patch between four black 

 spots on the top of the thorax ; a white spot on the top of the 

 hind thighs; thorax nearly or quite as long as the wings. 

 Length %& to T 6 g- inch to the apex of the thorax. 



This species varies in wanting the white spot on the top of 

 the thorax sometimes. It was first described by Mr. Say, 

 under the name of Aerydium ornatum* 



2. Tetrix dorsalis. Eed-spotted Grouse-locust. 



Rusty black, with ochre-yellow spots on the sides and legs, 

 and a large rusty-red spot on the top of the thorax ; wings 

 extending beyond the apex of the thorax. Length £ inch. 



3. Tetrix quadrimaculata. Four-spotted Grouse-locust. 



Ash-colored or dark gray above, variegated with black; 

 four velvet-black spots on the top of the thorax; wings 

 projecting beyond the extremity of the thorax. Length from 

 to- to -rV of an inch. 



This is a shorter and thicker species than the ornamented 

 grouse-locust. It is not uncommon in pastures from the first 

 of May to the first of June. 



4. Tetrix bilineata. Two-lined Grouse-locust. 



Ash-colored ; thorax paler, with a narrow angular whitish 

 line, on each side, extending from the head beyond the mid- 

 dle ; the angular portion including a lbng blackish patch on 

 each side ; wings, in the male, rather shorter than the tho- 

 rax, in the female longer. Length from & to more than 2 V 

 inch. 



* American Entomology, Vol. I. Plate 5. 



