NO. 2 THORACIC MECHANISM OF A GRASSHOPPER SNODGRASS 



85 



tween the two wing areas takes place along the anal fold (figs. 45 A, 

 50 A, AF), and is produced mechanically during the flexion of the 

 wing. The broad hind wings are folded in a complicated manner, to 



C Sc R M I 



\ \ \ 1 / 



2Cu "^A iCu lA 



A 



Sc^ R+M iCu 2Cu M Rs p ^i 



r~-vD 



Fig. 45. — The wings and wing veins of Dissosteira. 



A, fore wing, or tegmen. B, hind wing. A, anal veins, anal area of wing ; 

 I A, first primary anal vein; yA, seventh primary anal; C, costa; iCu, first 

 cubitus ; 2Cu, second cubitus ; /, intercalary vein ; i, j, secondary anal veins of 

 first anal plait; k, first concave anal vein; /;(, jugal area of wing; /, second con- 

 cave anal vein; M, media; F^ra. prcanal area of wing; q, basal support of anal 

 veins ; R, radius ; i^i, first branch of radius ; Rs, radial sector ; r, first anal plait 

 of wing ; R + M, united shafts of radius and media ; Sc, subcosta ; VD, vena 

 dividens. 



be described later, and when fully flexed are concealed beneath the 

 overlying tegmina (fig. 50 A). 



The area of an insect's wing presents usually three well-defined 

 regions, namely, a preanal region, an anal region, and a small, pos- 



