242 PROCEEDINGS OF SOCIETIES. 
found in the plumules of the Pieridz, described by him in a pre- 
vious paper. Fifty-three figures of the plumules, drawn by Mr. 
Sidebotham, were shown as illustrations of the subject. He said 
the points he desired to insist upon as likely to be useful in this 
investigation were—That the plumules were always identical in 
individuals of the same species, and mere varieties can therefore 
be detected by this test; and that, in very closely allied species 
which are difficult of distinction by the more ordinary characters, 
these scales will be often found to be different. 
Mr. Sidebotham read “ Notes on the Development of the Wings 
of Lepidopterous Insects.” He said that their great and rapid in- 
crease of size soon after the insect emerges from the chrysalis is 
caused by air, taken in through the spiracles, being sent ito the 
vessels of the wings; the membrane is expanded in consequence, and 
the scales, which were before packed under each other as closely 
as possible, are made to slide out until they remain in the fully 
developed wing like the tiles of a roof. He exhibited preserved 
specimens of the Currant moth and the Tiger moth, with the 
wings both in their small and in their expanded state, also a co- 
loured sketch of one of them, and it was seen that in the unex- 
panded state the wings lie flat, without any foiding, and all their 
markings are a correct representation in miniature of what they 
ultimately become, 
