ACRIDIIDAE ACRIDIINAE 41 



Genera of Leptysmae. 



a l . Head slightly shorter than the pronotum ; fastigium of 

 moderate size, with margins less compressed than in the alternate 



category. Arnilia Stal. 



a 2 . Head as long as or longer than the pronotum, strongly 

 exserted ; fastigium large, horizontal, noticeably narrowed anteri- 

 orly, the margins compressed, at least before the middle. 



Leptysma Stal. 



These genera occur in the extreme southern states along the 

 Gulf of Mexico and have one or two species each. 



Acridia. 



The only recognized genus is Schistocerca Stal, with numerous 

 species widely spread over the United States. The species need 

 careful revision. 



Melanopli. 



This group has its highest development in America and espe- 

 cially in North America ; its single Old World genus occurs in 

 the north temperate region of Europe and Asia and is not pecu- 

 liar to it but shared with North America, the half dozen genera 

 not found in our territory being exclusively Central and South 

 American. 



Genera of Melanopli. 



A l . Lateral margins of subgenital plate (last ventral segment) 

 of male, as seen laterally, straight throughout or very slightly 

 convex, never at all abruptly ampliate at the base. 



b l . Body exceptionally slender ; mesosternal lobes subattin- 

 gent in both sexes ; prozona three times as long as metazona. 



Gymnoscirtetes Brunei*. 



b 2 . Body not exceptionally slender ; mesosternal lobes in both 

 | \ sexes so widely separated that the interspace between them is 

 at most twice as long as broad ; prozona not more than twice 

 as long as metazona. 



c l . Interspace between mesosternal lobes of female decidedly 

 transverse, sometimes twice as broad as long ; of male some- 



