212 Annals Entomological Society of America [Vol. VIII, 
The wings, after the last larval skin has finally been cast, 
remain for a short time in their folded condition; they then 
unfold, decrease in thickness with an increase in their area. As 
a result of this the old hypodermal layers, just under the cuti- 
cula, are spread as a continuous layer in this position and have 
apparently received a considerable amount of the cytoplasm 
which was formerly in the perpendicular strands when these 
became shorter and thinner (Fig. 9). The nuclei, which in the 
last stage were all in the perpendicular strands, have nearly all 
wandered into the layers under the cuticula; a few still remain 
in the strands from which they later disappear. The middle 
membrane has become much thinner and, instead of being a 
fairly continuous layer, 1t here and there now assumes a zigzag 
shape; along its course can be seen very small and somewhat 
ovoid bodies, these are all that remain of those nuclei which, at 
an earlier stage, wandered into this layer from the hypodermis. 
During that period in the life of the pupa in which its body 
contracts and shortens the changes, noted in the last paragraph, 
are continued and become more marked. The nuclei of the 
perpendicular strands have all passed from these into the old, 
outer, hypodermal layers in which they now are arranged in a 
fairly even layer. The protoplasm does not in these layers 
become even but in many places surrounds each nucleus in a 
triangular mass, these at the base are connected with each — 
other but the apex of each points towards what remains of the 
middle membrane and is, in most cases, extended out into one 
of the perpendicular strands (Fig. 10). The perpendicular 
strands have become thinner and most of the protoplasm that 
they contained has entered the outer layers of the wing. The 
middle membrane no longer extends as a continuous layer 
through the median part of the wing but its zigzag course 
becomes more marked until finally it separates into a number of 
strands and can no longer be followed continuously as in all the 
earlier stages. This disappearance of the middle membrane 
becomes more marked until all traces of it are lost, the perpen- 
dicular strands then either pass across the wing from one surface 
to the other or they end blindly at some place along such a 
course. The failure to see all of the strands connected with 
both layers of the hypodermis is undoubtedly in part due to a 
study of thin sections. Many of the nuclei which earlier wan- 
dered into the middle membrane from the hypodermal layers 
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