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XXII. 
NOTES ON THE HABITS OF SOME OF OUR LEPIDOPTEROUS 
INSECTS. 
By Arthur Cottam, F.B.A.S. 
I.—The Butterflies. 
Read at Watford , 16 th December , 1902. 
The Lepidoptera, which are commonly known as butterflies and 
moths, are scale-winged insects, deriving their name from two 
Greek words— lepis, “ a scale,” and pteron , “ a wing.” 
However carefully a butterfly or a moth may he handled, it is 
impossible to avoid rubbing off a little of what is commonly called 
the “dust” that covers its wings. This dust is the scales, which, 
if examined with a microscope or a strong magnifying lens, are 
seen to he of beautiful and very various forms, and many of them 
brilliantly coloured. The scales are placed upon the wings like 
the tiles on the roof of a house, each row overlapping the row 
below it, the highest row being at the base of the wing next the 
body of the insect, and the lowest row on the hind margin forming 
an exquisite fringe. Taking advantage of this arrangement it is 
possible, if an insect has in any way got dusty, to brush the wings, 
if the brush is carefully passed outwards from the base of the 
wings, without rubbing off any of the scales. Brush the wings 
the other way and you will utterly spoil the beauty of the insect. 
I am frequently asked, What is the difference between a butterfly 
and a moth ? And very hazy notions seem generally to prevail as 
to how to distinguish them. So far as our British species are 
concerned there is no difficulty. They are distinguished by the 
structure of the antennae, as those horn-like organs are called 
which are placed upon the head just above the eyes. In the 
butterflies these are clubbed, and the butterflies are therefore 
called Bhopalocera, which means club-horned. The antennae of 
moths are never clubbed. They are very various in form and 
structure, some being hooked, some, like the thong of a whip, 
getting thicker to the middle and then tapering to a point, others 
are beautifully feathered, and some are comb-like. The moths 
are therefore called Heterocera, variously horned. 
What is the use of the antennae is not certainly known; so far 
as one can see, the insects appear to make little or no use of them, 
hut they are supposed to he organs of feeling, and possibly in 
flying they may help to direct the course of the insect. My own 
idea is that they are the organs by which insects smell. This 
sense is developed to a very high degree in all insects, whereas 
they appear to be perfectly deaf. No noise will disturb them. 
The Bhopalocera or butterflies form a very small portion of our 
Lepidoptera. The lists give 65 or 66 British species, but of these 
six are not believed to breed in this country, although they are 
occasionally, and some of them are frequently, taken here. Two 
