Psyche 
[June 
114 
stem of M. The structure of MA and of MP is essentially the same 
in the two genera. The anal veins of Dictyoptilus are similar to those 
of Eugereon except that they are not quite so strongly curved near 
the base of the wing. However, it is when we compare the hind wings 
of these two genera that we find the similarities most striking. Rs, 
after its origin from Rl, diverges away the same way in the two gen- 
era and then gives rise to the first of the pectinate branches. The 
media is curved in both genera and produces the strongly convex MA 
and after a very short interval MP divides to form the two main 
concave branches. CuA appears in essentially the same form in both 
genera. 
The close relationship between Dictyoptilus and Eugereon now 
seems obvious; the similarities of the fore wings might be due to 
convergence but the similarities of the remarkably specialized hind 
wings, even in minor venational details, make this explanation unten- 
able. The affinities of these two genera have two interesting 
implications regarding Eugereon. Since the hind wing of Dictyoptilus 
is better and more extensively known than that of Eugereon, our 
previous interpretations (Handlirsch, 1906) of the venation of 
Eugereon now seem to require modification : the vein which has been 
interpreted as the media in the hind wing is actually the radial sector 
(Rs) and the former cubitus now turns out to be MA and MP. It 
might be noted in this connection that Handlirsch’s figure of the 
hind wing of Eugereon (1906) shows the very beginning of a branch 
originating from the vein herein indicated as Rl. Since Rl very rarely 
carries branches in any insect (except distally), Handlirsch apparently 
identified this vein as the base of the radial sector, which would, of 
course, be consistent with his interpretation of the next vein as the 
media. However, no fork or branch of this vein (Rl) is shown by 
Dohrn in his original figure of Eugereon or by any of the other 
workers who have studied the fossil, and none shows in a photograph 
of the specimen sent to me by the late Dr. Paul Guthorl. 4 Further- 
more, it is now obvious from the convexities and concavities preserved 
in the hind wing of Dictyoptilus that the subsequent vein (herein 
designated as Rs) is a concave vein and that all of its branches are 
concave; if this vein were the media, it should (in the Palaeodictyop- 
tera) be convex or at any rate have a convex anterior branch (MA). 
The second implication with respect to Eugereon is the shape of the 
wings. Although only the basal portions of the wings are preserved 
4 The figure of Eugereon included in the Osnovy (B. P. Rohdendorf, 1961, 
figure 40B) shows the branch on Rl, but that illustration was copied from 
Handlirsch, 1906. 
