714 The American Naturalist. [August, 
v. in Hepialus humuli Fig. 1, and in Neuronia, Fig. 4). I pre- 
sent a figure of the venation of the fore wing of Panorpa sp. 
which should be examined in connection with the jugate and 
trichopterous wings for the noting of this tendency of disap- 
pearance of the cross veins, and for the persistence of the mid- 
wing cross veins. It is worth while, in passing, to note also 
the general agreement in venational character of the mecop- 
terous wing with the trichopterous and lepidopterous wings. 
The more generalized character of the Panorpa wing is mani- 
fest in the point of number of radial and medial branches and 
in the abundance of cross veins. As I have pointed out else- 
where, this disappearance of cross veins in these three groups 
proceeds coincidently with the development of the wing-scales, 
which serve to strengthen the wing-membrane. 
Not alone in character of venation but in character of wing- 
clothing, as pointed out in a previous paper, and in the mode 
of tying the fore and hind wings of each side together for the 
sake of sychronity of movement in flight, do the jugate and 
trichopterous wings show obvious resemblances. The well- 
known scale-hairs of the Trichoptera are simply the true lepi- 
dopterous scale in generalized state. Nor are these trichopter- 
ous scales always of so generalized condition as an examina- 
tion of a limited number of wings might lead one to believe. 
There are many instances among the caddice-flies of the pres- 
ence of well developed scales. In Fig. 7 well-specialized scales 
from the fore wings of two species of Setodes are shown at c 
and d. Ihave been specially interested to note in the wing 
clothing of Mystacides punctatus (see a and b, Fig. 7) in addition 
to the numerous broad scale hairs, a sprinkling of conspicuous 
large, flattened, bulbous, white scales, which present exter- 
nally the peculiar characters of the variously modified scent- 
scales or androconia of the male butterflies. 
The essential structural difference between the Jugate and 
Frenatæ on which the two groups were separated by Prof. 
Comstock is that displayed by the two methods of uniting the - 
wings of each side during flight. The jugate moths have fore 
t Author. The Classification of the Lepidoptera, AMERICAN NATURALIST, V. 
XXIX, no. 339, pp. 248-257, March, 1895. 
