322 



AN INTRODUCTION TO ENTOMOLOGY 



Unlike the dragon-flies, the damsel-flies are comparatively feeble 

 in their flight. They are found near the margins of streams and 

 ponds, in which the immature stages are passed. 



Most of the features in the venation of the wings of dragon-fliti 

 described on earlier pages are also characteristic of the wings of damse'i- 

 flies. Figure 368 represents an entire wing of Lestes rectangularis; 



Fig. 369. — Base of fore wing of Lestes rectangularis: br, the bridge; q, quadrangle; 

 sq, subquadrangle. 



in this figure o indicates the oblique vein, and hr the bridge. In 

 Figure 369 the base of this wing is represented more enlarged, and 

 the principal veins are lettered. 



In the suborder Zygoptera the cubitus and the first branch, vein 

 Cui, extend in a comparatively direct course from the base of the 

 wing outward (Fig. 369); the abrupt bends in these veins in the 

 region of the triangle, which are so characteristic of the Anisop- 

 tera, are only slightly developed here. This results in the areas 

 corresponding to the triangle and the supertriangle of the Anisop- 

 tera being in direct line and forming an area which is often 

 quadrangular; this area is termed the quadrangle (Fig. 369, q). In a 



large part of this or- 

 der the cross-vein sep^ 

 arating the parts of 

 the quadrangle corre- 

 spond ingto th e triangle 

 and the supertriangle 

 of the Anisoptera is 

 lacking, in which case 

 the quadrangle con- 

 sists of a single cell 

 Fig. 370.— Base of wing of Heliocharis. ^~*~-^ (Fig. 369, g). In SOme 



members of this sub- 

 order it is present; in Figure 370, representing the base of a wing 

 of Heliocharis, the two cells of the quadrangle are labeled t and .j to 



