DEROTMEMA.— TRACHYRHACHIS. 173 



Hab. North America, Northern New Mexico 1 2 , and Colorado (coll. U.S. Nat. 

 Mus.), Silver City, N. Mexico (coll. L. Bruner). 



While not reported so commonly from Southern New Mexico, it is possible that it 

 also reaches across the international borders.] , 



[4. Derotmema saussureanum, Scudd. 



Derotmema saussureanum, Bruner, MS. 1 



Derotmema saussureanum, Scudd. Proc. Amer. Acad. Arts & Sci. xxxv. p. 391 (1900) 2 . 



Bab. North America, Southern California, numerous localities ; South-western 

 Arizona (L. Bruner 2 ). 



Very likely occurs in Sonora and Lower California.] 



5. Derotmema haydeni, Thomas. 



(Edipoda haydeni, Thorn. Ann. Rep. U.S. Geol. Surv. Terr. v. pp. 460, 461 (1872) * ; Sauss. 



Addit. Prodr. CEdip. p. 171 (1888) \ 

 Derotmema haydeni, Bruner, Ann. Rep. Nebr. Bd. Agr. 1896, p. 132 (1897) 3 ; Scudd. Proc. Amer. 



Acad. Arts & Sci. xxxv. p. 392 (1900) \ 

 Derotmema brunnerianum, Sauss. Prodr. OEdip. pp. 155, 156 (1884) 5 . 



Hab. North America, from Eastern Montana to Texas 1_5 . — Mexico, Villa Lerdo, 

 Durango, and Comancho, Zacatecas (L. Bruner : <S 2 )• 



The Mexican specimens of this species are all yellow-winged, while in the United 

 States, especially northward, both red- and yellow-winged individuals occur. 



TEACHYRHACHIS, Scudder. 



(Edipoda, Latreille (in part.) et auctt. 



Psinidia, Stal, Recens. Orthopt. i. p. 133 (1876). 



Psinidia (Trachyrhachis) , Saussure, Prodr. CEdip. pp. 160, 162 (1884). 



Trachyrhachis, Scudder, Ann. Rep. Chief Eng. 1876, p. 512; Bruner, Ent. News, xvi. p. 259 



(1905). 

 Mestobregma, Scudder, Bull. U.S. Geol. Surv. Terr. ii. p. 264 (1876). 



The present genus is composed of rather small or medium-sized grasshoppers. 

 In their distribution most of the somewhat numerous forms are at home on the open 

 prairies of the Middle and South-western United States. A few of the species are 

 confined to special food-plants and are restricted in their distribution, while others 

 enjoy a wide range. The various forms may be separated by the subjoined table ; -less 

 than half of them belong to Mexican territory. 



