HYMENOPTERA 



81' 



The difficulty already alluded to in comparing the venation found in this 

 order can be solved in one of two ways, either by assuming 1st. a great 

 amount of fusion of the elements of the venation and of rearrangements of 

 position, or 2nd. simply the suppression of certain parts. 



The former has been worked out in detail by Comstock and Mac Gillvray 

 They assume that the media is fused with the radius until just before the node 

 where it is turned obliquely backward to the base of the cubitus and then 



Figure 54. Venation of Trichopteryg-idge. A. and B. Cliloropsyclie. C. Helicopsyche. 

 1-5 notation of veins used in that order. St. area in which stigma is supposed to 

 develop. O. veins which are vestigial in Hymenoptera. 



Figure 55. Thi-ee interruptions of veins on fold lines 



turned outward again to the base of the first recurrent which is its posterior 

 branch; both branches subsequently fork and ultimately the tips unite as 

 follows: the upper fork with two branches of the radius, the two middle 

 forks with each other thus enclosing the third discal cell, and the lower fork 



