31 
dinally, and by so doing the scales of full-size and in situ are 
simply drawn wider and further apart, but of growth there is none. 
This can be seen by cutting open the pupa-case just before the 
emergence or taking the wing of a recently emerged insect; this 
must be done at once, because in some cases within ten minutes of 
emergence the wings are of full-size. There is, therefore, no re- 
plenishing of waste, nor reparation of parts in the scales of Lepi- 
doptera as in the hairs of the Mammalia. Nor can we trace in all 
scales the cuticular layer, cortical and medullary substance of such 
hairs; we seem to obtain a cortical substance with or without a 
cuticular layer and sundry rib-like strengtheners, which have given 
rise to the diversities of opinion as regards structural markings. 
There is another curious fact sometimes noticed, viz., that there 
appears to be a power on the part of the insect to raise the rows of 
the scales, as well as to inflate some scales. We have often found 
the scales on the wing of a butterfly, caught or killed in flight, not 
lying flat on the wing membrane, but raised on it at a more or less 
acute angle, as though in flight the insect possessed the power of 
raising the rows of scales; this may, if we imagine the power of 
inflation of the scales, as well give greater buoyancy to a butterfly 
or moth in flight. We have every reason to believe this holds true 
of some scales, if so it would give to the wing membrane with its 
resources a power not accorded to it in the manuals of Entomology. 
It is time we passed on to what is after all the especial point your 
worthy President wished me to talk about, viz., those scales which 
are characteristic of sex, and by this we mean are found only on 
male insects. Itis now twelve years ago, I started one afternoon 
with a medical friend to look for a certain fern, said to grow about 
twelve miles from Brighton. We got out of the train at Hassock’s 
Gate Station, and diverged a little from our course to see whether 
Neottia Spiralis, the orchis which Darwin watched the bees fertilizing 
by carrying the pollen masses from one flower to another, was in 
flower. While searching for this plant several blue butterflies got 
up. My friend and I managed to catch several; this fact is strongly 
impressed on my mim, because after walking nearly a mile, we 
retraced our steps to search for a stethoscope which, in his eager- 
ness of the chase, had dropped from my friend’s hat when catching 
a “blue.” On our way we both talked over the question of why 
we had not been able to find ‘‘battledore” scales on blue butterflies ; 
was it because they were only on one kind? for though we had both 
searched for them on the part described in the Micrographic Dic- 
tionary, p. 564, under ‘‘ Polyomanatus,” and we had neither been 
able to find them. The words there run :—‘ The scales upon the 
under surface of the wings of P. argiolus and P. argus have been 
proposed as test objects. They are of two kinds—one resembling 
in structure the ordinary scales of insects, the other of a battledore 
form.’’ What my friend did with his “blues” I do not know; I 
