THE SPECIES OF THE ORTHOPTERAN GENUS 



DEROTMEMA. 



By Samuel H. Scudder. 



Received February 8, 1900. Presented February 14, 1900. 



The genus Derotmema was founded by me in 187G upon a single 

 species found in northern New Mexico. Eight years afterward Saussure, 

 who had not seen this species, added two others, regarded as new, one of 

 which has since turned out to be identical with a species described in 1871 

 by Thomas as an (Edipoda coining from Colorado and Wyoming. None 

 have since been added to the list, but I have for a long time had in my pos- 

 session other new species, mostly collected by me in the Rocky Mountain 

 region ; and recently Mr. A. P. Morse has brought home from the 

 Pacific coast still others, so that I am now able to refer eight species to 

 this genus. 



They easily fall into two groups, in one of which the insects are of 

 relatively small size with very prominent eyes and rather long antennse ; 

 the tegmina are distinctly tapering with nearly straight costa and the inter- 

 calary vein suhequidistant from the median and ulnar veins ; while their 

 more conspicuous markings are confined to the costal and inner edges. 

 In the other, the insects are of larger size, with normal eyes and ratlier 

 shorter antennae ; the tegmina do not taper, the costa is arched, and the 

 intercalary vein approaches the median much more closely than the ulnar 

 vein ; while the markings are in no way especially attached to the 

 margins of the tegmina. In both, the wings are colored at the base and 

 crossed by an extramesial fuscous band. 



Saussure (Prodr. CEdip., 154, note) has pointed out that a more 

 correct derivative from the Greek words forming the basis of the generic 

 name would be Tmetodera, and accordingly I apply this term to one of 

 these two main groups, but not the typical one, for which latter the 

 original form is retained. 



Derotmema is a desert-inhabiting genus of slender QEdipodina?, found 

 largely on and about sage-brush and often simulating it in color. It is con- 

 fined to the western half of the United States, from the western margin 

 of the Great Plains bordering the Rocky Mountains to the Pacific. 



