378 



THE WINGS OF IIYMENOPTERA 



In Oryssus (Fig. 397, ci), a form in which there has been a great reduction 

 of the wing-veins, these parts are both wanting. But in the other forms 

 shown in Figure 397 these parts are retained. In the first three (Fig. 397, 

 a, b, c) these two parts taken together constitute a shghtly bent vein; in 

 the fifth (Fig. 397, e) they form a perfectly straight vein ; and in the last 

 (Fig. 397, /), one that is slightly bent. 



In the last two forms, and in nearly all other members of the Clisto- 



Fig. 398. — A fore wing of Janus abhreviatus. 



gastra, there is no trace of that section of the radial sector extending from 

 the radio-medial cross-vein to the stigma ; hence there is nothing to indicate 

 the compound nature of the vein composed of the radio-medial cross-vein 

 and that section of the radial sector between this vein and the radial cross- 

 vein. For this reason this serial vein was formerly believed to be merely 

 the radio-medial cross-vein. It should now be designated as vein r-m 



The switching of the base of the radial sector and the changes described 

 in the two preceding paragraphs were not understood until the publication 

 of Dr. MacGiUivray's paper in 1906. As Comstock's Manual for tlie Study 



Sc^R'rM 



Fig. 399. — A fore wing of Odontaulacus cdilus. 



of Insects, in which was made the first attempt to apply the vmifonn 

 terminology of the wing-veins to the wings of Hymenoptera, was published 

 in 1895. the figures of wings of the Clistogastra in that work are, in some 

 respects, incorrectly lettered. 



