204 



BRITISH ORTHOPTERA. 



lii an elytron of a normal member of the Acridiodea,. 

 which is fairly typical of elytra and wings of the 

 Orthoptera, the principal nervures are : 



1. The costa, which constitutes tlie fore margin of the 



elytron. 



2. The sub-costa in two branches. 



s c 



FIG. 23. Elytron and Aving of an Acridian grasshopper. Nervures .- 

 c, costa ; s, siibcosta ; R, radius ; M, niedius ; cu, cubitus ; 

 AJ, first anal ; A 2 , A 3 , etc., remaining anal nervures ; D, dividing 

 nervure. 



3. The radius, which, at the base, is closely associated with 



the sub-costa. 



4. The medius. 



5. The cubitus, which is closely associated with the medius 



at the base, the region between them being distinctive 

 in one case 8. lineatus. 



6. The first anal nervure, which is separate from the 



remaining anals. 



7. Between the first and remaining anal nervures is'jthe 



first anal fold (in which is developed in some Orthop- 

 tera the dividing nervure not a primary one). 



