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APPENDIX 
when looked at from beneath) a rather close net-work of largish air-vessels, 
with red-brown, transparent points enclosed in the meshes. 
The brand on Gallidryas argante is also traversed by branched arbo¬ 
rescent air-vessels. It is somewhat paler than the surrounding area, from 
which it is not sharply demarcated, but after removal of the scales it stands 
out more distinctly as a dull spot. This brand lies in the obtuse angle 
between the subcostal and its branch, and is separated by a pale border 
from both veins, from which air-vessels pass into it. It is about 3 mm. 
long, by 0*6 mm. in greatest breadth. The mane which covers the spot 
is composed of hairs of about 5 mm. long, arising from a strip, about 
1*3 mm. in breadth, which extends from the base of the cell for about 
10 mm. along the subcostal. 1 
Having therefore demonstrated by actual observation that the purpose 
of the patches and hair-tufts in the males of Gallidryas argante , Thecla , 
Prepona laertes and Dircenna xantho , species from widely differing families, 
is to exhale scents, which are probably agreeable to their females and 
entice them to pair, I am led to infer that this is the meaning of all 
similar structures on the wings of male Lepidoptera, not only because of 
the unmistakable similarity amidst such great diversity, but even more 
on account of the previously mentioned peculiarities which render them 
especially suitable for such a purpose. They are usually sheltered from 
exposure to the air, enclosed between the fore and hind wings or in some 
other manner, or at least, while at rest, concealed between the closed 
upright wings. Thus the scent is not diffused at the wrong time and so 
wasted, but collects between the densely packed scales, among the hairs, 
brushes or manes. One could hardly find a more effective method of 
employing any odoriferous substance, than that of saturating with it the 
hairs of a brush, and then suddenly opening them out in all directions, so 
as to provide an enormous surface for evaporation. 
Just as the Ageronias, four species of which I had an opportunity of 
observing in some numbers during the past summer, only make the 
remarkable crackling sound on the wing and during courtship, so also in 
all probability, the butterflies equipped with brands, tufts, etc., only 
distribute their scent under the same circumstances. 
I recently captured a pair of Hesperia orcus , which were fluttering 
close together, and appeared to be almost on the point of pairing. When 
I took out the male, which had been killed by a pinch while still in the 
net, I found that the costal fold of one side was raised and spread out in 
the plane of the wing. I had never seen such a thing on any other 
1 Argante is accompanied in this locality by a very similar paler species or variety 
which agrees very well with Boisduval’s description of C. agarithe , and emits a scent 
just like that of argante. The brand in this form is larger, not only extending to 
the subcostal and its branch, but filling the acute angle between these two nervures. 
Among the specimens I happen to have in hand, I find no transition forms between 
the two.—F.M. 
