98 
Ammoniacal Solution of Copper. I am inclined to the belief 
that cotton hairs do not contain spiral vessels properly so- 
called. I think that the spiral apparatus, which has been 
described by Mr. C. O’Neill and Mr. Heys as spiral vessels, 
can be clearly traced to a mechanical action which the 
solvent exerts on the vegetable cell. At some future time I 
hope to illustrate this to the Section. — Yours truly, 
“ J. B. Dancer.” 
Mr. Heys explained that he had not intended to describe 
the cotton hairs as containing spiral vessels, in the botanical 
sense of that term, but had spoken of the appearance within 
them as that of a spiral thread. 
Mr. Watson read a communication “On the Plumules or 
Battledore Scales of the Lycsenidse,” in which he showed that 
they will serve the purposes of identification by exhibiting 
generic and specific alliances, and differences similar to those 
found in the plumules of the Pieridse, described by him in a 
previous paper. Fifty-three figures of the plumules, drawn 
by Mr. Sidebotham, were shown as illustrations of the sub- 
ject. He said the points he desired to insist upon as likely 
to be useful in this investigation were — That the plumules 
are 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 
often be found to be different. 
Mr. Sidebotham read “Notes on the Development of the 
Wings of Lepidopterous Insects.” He said that their great 
and rapid increase of size soon after the insect emerges from 
the chrysalis is caused by air, taken in through the spiracles, 
being sent into the vessels of the wings ; the membrane is 
expanded in consequence, and the scales, which were before 
