76 
On the Battledore 
[Monthly Microscopical 
Journal, Aug. 1, 1869. 
flat, like empty bags, under the superincumbent scales. By tbis 
supposition, as regards the functions of these plumules, we may 
account for the superior strength and power of flight which the 
males possess over the females. 
Here, then, is a field open for great microscopical research — a 
field which promises variety of interest the further it is pursued. 
New forms of scales will probably be discovered in many genera 
hitherto unexamined ; the attention should not, however, be directed 
solely to the observation of these plumules, as all the forms of 
scales are worthy of careful study. 
In the following families I have found no plumules, viz. Papi- 
lionidse, Acraeidae, Morphidae, Brassolidae, Eurytelidae, Libytheidae, 
and Hesperidae. In the DanaidaB I have found them only in the 
genus Euj)lsea. In the Heliconidae only in the genus Keliconia, 
unless Eueides is to be considered as belonging to this family, and 
not to the Nymphalidae, which position is justified by the form of 
the plumule. In the Nymphalidae I have found them in several 
genera, principally of the Argynnis group ; and notably in Athyma, 
but not in Neptis. In the Satyrida3 in several genera, and the 
well known scale of Ej^inejpliele Janira is a good type of the generic 
form. 
And now passing to the Lycaenidae, I beg to refer to the battle- 
dore scales (so called) which are represented in the accompanying 
plates. They seem to be intended to serve the same office as the 
plumules in other families, whatever that may be. They exhibit 
similar generic and specific alliances and differences, and answer 
the same purpose of identification of species. 
They are most beautiful microscopic objects, and interesting in 
a physiological sense, displaying how variously and marvellously 
creative power has worked in these minute organisms, always with 
the same end in view. 
The especial function of the plumules of the Pieridae has been 
suggested by me to be that of air-vessels, giving buoyancy to the 
insects ; and these Lycaena scales, by their balloon shape, are emi- 
nently fitted for this service, and even in a greater degree render 
it probable that certain Lepidoptera possess at least two kinds of 
scales, performing different offices in the economy of the insects. 
These plumules are attached to the wings by an apparently hollow 
peduncle. They show striae-hke ribs, suitable for binding, strength- 
ening, and distending or contracting their balloon-Hke forms ; these 
ribs are more or less beaded or articulated, by which different scales 
are bound or bent in various ways. The end opposite to that of 
insertion is closed or covered with apparently cihary apparatus. 
And they lie in rows between and under the ordinary scales, which 
may therefore be elevated or depressed at the pleasure of the insects 
by the regulated inflation of the plumules. They differ in separate 
species in every conceivable way — in form, in the number and 
