1930 ] 
Permian Insects of Kansas 
369 
broad wings, exemplified in the Paleodictyoptera. But 
when the venation of the wing is not altered during the 
process of change in the shape of the wing, the broadening 
is of specific or even individual importance only. Many 
examples of this can be found in recent groups. In the 
Asilid genus Leptogaster the wings are frequently sub- 
petiolate, while in Ospriocerus and Pogonosoma they are 
remarkably broad. In the Empidse the wings are often 
subpetiolate, but in some species, as Rhamphomyia, they 
are enormously broadened, and almost oval. In this latter 
family also the broadening of the wings is frequently a 
secondary sexual characteristic of the male. But in none 
of these insects is the venation changed as the wings widen, 
aside from shift in the direction of the veins in the anal 
region. On the other hand, when the process of change in 
shape is accompanied by numerous modifications of the 
venation, then the breadth is of great phylogenetic value. 
I have already shown the impossibility of deriving the 
anisopterous dragon-flies from the petiolate Zygoptera, 
for here numerous changes in the venation would be neces- 
sary. In the genus Permohymen, however, we are dealing 
with the former type of modification in the shape of the 
wing, where there is no alteration of the veins. Aside 
from slight difference in the direction of the anal veins, 
the venation is exactly like that of Protohymen, which is 
as petiolate as the Carboniferous Megasecoptera. The 
assignment of such a broad-winged insect as Permohymen 
to the Megasecoptera is therefore not at all objectionable. 
The pterostigma in the Protohymenidse is a simple struc- 
ture, much less of a specialization than Tillyard had sup- 
posed. In Aspidohymen there is no pterostigma, R1 being 
remote from the costal margin at this point; but there is 
a strong, oblique cross-vein connecting R1 with the costa 
in the pterostigma region. In Protohymen permianus 
R1 fuses with the costa up to the pterostigmal area, where 
it diverges downward to the apex of the wing; the ptero- 
stigmal cross-vein is present, and even more strongly de- 
veloped (R1 of Tillyard). In Protohymen elongate R1 is 
slightly removed from the costa in the pterostigmal region, 
