712 The American Naturalist. [August, 
caddice-fly collected by me in Colorado (see Fig. 5), the reality 
of the correspondence is apparent. In the fore wings of all the 
simple unbranched sub-costa (II), the 5-branched radius (III,- 
III,), the persisting stem of media (V) coalescing at its base 
with cubitus (VII), the three branches (four in the Colorado 
trichopteron) of media (V), and the reduced anal field, are com- 
mon characters. In the hind wings, the general character of 
the venational uniformity is only varied by differences which, 
Sa vita Vila 
Fic. 4. Wings of Neuronia, sp.; c. v., cross Fic. 5. Wings of undetermined 
vein; j. jugum. caddice-fly ; j. jugum. 
in themselves, are additional evidences of a community of 
plan. One of the caddice-flies differs from the other in those 
correlated characters which have been pointed out by Prof. 
Comstock as characteristic of the tendency of specialization in 
the lepidopterous wing, viz., a tendency towards the coales- 
cence (or disappearance) of the radial branches and increasing 
reduction of the anal area manifested by a loss of anal veins. 
In the hind wings of the Colorado caddice-fly (see Fig. 5) there 
are but four radial branches (IIL, III,,,, and III, and ITI,), 
and the anal veins (VIII, IX, XI, XIII), while two more in 
number than in Micropteryxz or Hepialus, are less in number 
than in Neuronia. 
It is beyond the scope of this paper to attempt any discus- 
sion of the lines of specialization exhibited by the wings of the 
Trichoptera, but it is an obvious and interesting fact that the 
