254 THE AMERICAN NATURALIST.  [VoOL. XXXII. 
(Fig. 25) will serve to illustrate the type of venation charac- 
teristic of this suborder. 
In the fore wing the branches of radius appear to present a 
complicated arrangement, but this is merely due to the anasto- 
mosis of veins Æ, and 4; except for this the radial sector has 
preserved its primitive type. In this wing the bases of veins 
Mz and M, have migrated towards the cubitus, so that cells rst 
Mz and 2d Mz are not opposite each other (cell 1st M2 is the 
small triangular cell near the center of the wing). 
In the hind wing a great reduction of the subcosto-radial 
Fic. 25.— Wings of a Prionoxystus. 
area of the wing has taken place. This has been brought 
about in two ways: first, veins Sc and Rx coalesce from the 
margin of the wing nearly to the base of R1;! and second, the 
radial sector is reduced to a single vein, Æ, 
We have space to point out only one, the most important, of 
the ways in which this type is modified in the Frenate. It will 
be observed that the basal half of the wing, being traversed by 
the main stems of all of the veins, is stiffened to a great extent. 
Evidently, from what has taken place in the more specialized 
1In pupe of Frenate the subcostal trachea and the first branch of the radial 
trachea are distinct. This fact was first pointed out by Spuler. 
