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plumules (so called) of the Lepidoptera ; they were princi- 
pally of the Pieridse family, all being drawn by the camera 
to one magnifying scale of 350 times linear measurement. 
He also showed a number of these insects which yield 
the plumules, and drew attention to their similarities and 
differences ; noticing that some butterflies, closely allied in 
all other respects, display corresponding but distinctive 
resemblances in this also, while others as nearly allied 
possess very different forms of plumule ; and that the size 
of the insect does not govern the size of the plumule, some 
large species having small plumules, and some small species 
having large plumules; some striking examples of these 
facts were exhibited. About 30 species of the insects them- 
selves, with drawings of their own plumules placed by their 
side, afforded an easy mode of observation of the marvel- 
lously varied types of form displayed in these curious scales. 
Besides the drawings of the Pieridse family were a few of 
the Danaidse (Genus Euploea) and Nymphalidse, and Mr. 
Watson expects to exhibit shortly a large number of 
drawings from these families, and from the Heliconidse, 
Satyridm, and Lycsenidse. He drew attention to some hair- 
like scales tufted at their apex, which occur on some species 
of the Genus Argynnis (to one of which he had previously 
alluded in his last paper), and showed drawings of them 
side by side, with the true plumules and specimens of the 
insects themselves, from which both were taken. Whether 
or not these hair-like scales possess value for the determina- 
tion of species is at present uncertain, but there can be no 
doubt of the plumules wherever found in all genera serving 
for that purpose. 
The feathery tip of the plumules is very fragile, more so 
in some species than in others : slides are often covered 
with the debris : the drawings cannot represent their natural 
luxuriance in life. 
