266 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Tomonotus pseuilo-nietanus, Thos. Near Canon City, Colorado, and near Fort Fetterman, 

 Wyoming. 



Stauronotus Elliotti, Thos. Colorado and Wyoming. 



(Gryllus) formosus, Say. Southeastern Colorado. A new genus will have to be estab- 

 lished for the reception of this species. 



Acrolorilutus hirtvpes, Thos. Near Canon City, Colorado, and at Fort D. A. Russell 

 Wyoming. 



Sienobothrus obwnus, Thos. Southern Colorado. 



Stcnobotlirus brunneus, Thos. Colorado and Wyoming. 



Sienobothrus qiiadrimaculatus, Thos. Colorado and Wyoming. 



DESCRIPTIONS. 



Although most of the following species have been described by me, 

 and the descriptions published in the " Proceedings of the Academy of 

 Natural Sciences, Philadelphia," for 1870, (pp. 74-84,) yet it is proper 

 that the descriptions should be inserted here, as they constitute a part 

 of the work of the expedition. Those only will be marked as new which 

 are here described for the first time. 



I follow the arrangement adopted by Scudder in his catalogue, although 

 it is not altogether the one I should prefer. 



LOCUSTARLE. 



ANABRUS, (HALD.) 



The characters of this genus were not fully given by Professor Hal- 

 dernan when he established it, and those subsequently added by G-i- 

 •rard are scarcely sufficient to distinguish it from other closely allied 

 genera. Having both sexes of three species, I give the following as 

 the principal characters : 



General character : Head large, smooth, advanced in front between the 

 antennee. Pronotum selliform, extending over the base of the abdomen ; 

 rounded and smooth; anterior portion of the sides reaching below the 

 eyes ; posterior margin and angles round. Presternum bidentate ; pos- 

 terior angles of the meso-sternum elevated and acute. Elytra very short, 

 having the form of scales in the males ; covered by the pronotum in the 

 females. Antenna? longer than the body, sometimes extending beyond 

 the ovipositor. Eyes ovate; labrum round; maxillary palpi twice the 

 length of the labial, the three outer joints nearly equal, terminal enlarged 

 at the tip. Abdomen stout, of moderate length ; the sub-anal plate of 

 the male large, slightly notched at the tip, furnished laterally with filiform 

 appendages which appear to be articulated at the base ; the cerci (or 

 substituted appendages) sub-cylindrical, enlarged and generally bifurcate 

 at the extremity. Ovipositor long, bent beyond the middle. Cerci in 

 the female small and generally hairy. Legs slender ; posterior pair very 

 long; femora enlarged next the body, but slender and straight 'beyond 

 the middle, as long as the body (omitting the head) ; posterior tibia 

 long as the femora, slender ; all the tibiae provided with four rows of 

 spines, the anterior rows often scattered and irregular. A stout dentic- 

 uloid process above the anterior coxa. The tarsi broad, soles concave ; 

 third articulation cordate. 



This genus differs so slightly, in description, from Thyreonotus (Serv.,) 

 that there is scarcely a necessity for its retention ; but an examination 

 of the species is necessary to decide this point. A purpurascens (Uhler) 

 not having the prosternuni spined, has been removed to Thamnotrkon, 

 (Fisch.) 



A. Stevensonii, Thos. Syn., A. Stevmsonii, Thos. (Proc. Acad. Nat. 

 Sci., Phila., 1870, p. 75.) — Female: Purple mottled with yellow; form 



