0. 1331. 



DRAGON-FLY WING VENATION— NEEDHAM. 



745 



ffork is thus unilateral. In such genera as Calopteryx (fig. 34) and 

 ^Yestalis (fig. 41), vein J/i+o reunites with the radius — completel}^ fuses 

 with it — only to separate again, after which its base appears as a cross 

 [Vein and its distal end as a branch of the radius." The longest of the 

 sectors between veins J/^ and ilQ closely parallels vein J^, with all 

 the- shorter sectors liefore it. The stigma tends to atrophy, more 

 rapidl}^ in the males. The quadrangle becomes unusualh^ elongated, 

 and is almost alwaj's convex on its anterior side and traversed by a 

 number of cross vems, among which the identity of the typical one is 

 never evident. Vein Chu, just beyond the quadrangle, sets off a recur- 



Fig. 34. — Calopfcryx maculata Beauvois, fore wing and base of hind wing. 



rent liranch for the support of the anal angle of the wing. The longer 

 interpolated sectors tend to become attached as forks to the front side 

 of the principal veins, and to become set in opposition to the same 

 beyond the point of their attachment. Vestalis (fig. 41) illustrates 

 well the culmination of nearly all of these tendencies. 



A short side line includes only ILtcerlna and Lars. The tendencj' in 

 these is neither toward narrowing the wing at the base nor widening 

 it beyond, but it is found evolving a unique transverse wing brace out 

 of the bases of the cubital branches. (Plate LI, fig. 4.) 



"Thus the radius gained its typical complement of branches, which enabled 

 Redtenbacher to see in Calopteryj; the form of wing from which all other Odonate 

 wings might be derived! (Ann. k. k. naturhist. Hofmus. Wieu, I, 188G, p. 1(37.) 



