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Permian Insects of Kansas 
367 
branches, R2, R3 and R4 + 5. The next vein is the media, 
which is fused with R basally according to Brongniart’s 
figure; it diverges posteriorly a short distance before the 
origin of Rs, and then divides into its two main branches, 
MA ( + ) and MP (-). Shortly after its origin MA bends 
upwards towards Rs and is connected with it here by 
a short, stout cross-vein. MA is unbranched, but MP is 
forked near the middle of the wing. Cu separates from 
R close to the base of the wing and promptly divides into 
Cul and Cu2. In some of the Megasecoptera, as Mis- 
choptera (plate 30, fig. 6), the anterior media (MA) not 
only bends towards Rs, but actually fuses ivith it for a 
short distance; and Cul diverges towards MP at its base. 
Now in Aspidohymen, the Russian Protohymenopteron 
(text fig. 4), Rs originates as in the Megasecoptera; R2 + 3 
and R4 + 5 separate off as in Aspidothorax, but the former 
is unbranched. Hence, the structure of the radial sector 
in Aspidohymen is readily derived from that of the Megase- 
coptera by the elimination of the fork in R2 + 3. 
When we pass to the more highly developed wing of 
Protohymen, we find that MA has fused with Rs at its 
base, just as in some of the Megasecoptera. The free basal 
piece of MA, between its origin and junction with Rs, is 
very long and decidedly convex, not flat like a true cross- 
vein, as it was interpreted by Tillyard and Martynov. 
Now if we examine the posterior media in the Proto- 
hymenoptera we at once note that it is not forked as in 
the Megasecoptera ; the posterior branch of MP is the other 
vein which has been lost in the Protohymenoptera. In cer- 
tain of the Megasecoptera, as I have already mentioned, 
the basal part of Cul curves upwards towards M, just as 
MP approaches Rs. Unfortunately, this part of the wing 
of Aspidohymen is missing, but in Protohymen yermianus 
there is a short vein, resembling a cross-vein, between 
the base of Cul and R (see fig. 11). In Protohymen elon- 
gatus, Permohymen, and Doter, Cul bends upward and 
actually fuses with R at this point. Now in order to 
obtain this condition present in Protohymen from that 
of the Megasecoptera, we have only to suppose that Cul 
coalesced with MP at the base just as MA fused with R. 
According to this interpretation the “cross-vein” between 
