British Butterflies

by Alexander Morrison Stewart

PLATE 2.
[Method of Setting with Bristle and Braces]

While he is drying his wings and preparing for a life amongst sunshine and flowers, we might spend a few minutes with him ere he leaves us, and the more so, as now he looks his very best, arrayed in all his new-found finery. Such wings! no wonder he looks proud as he slowly opens and closes them, repeating this action over and over again as if to prove their smooth working before he launches forth upon the air.

And the wonderful pattern of these wings is all built up of tiny scales placed as regularly as the slates on a roof. Your pocket-lens will show you much of this, but to examine the individual scales, their various shapes and structure, you will require a compound microscope. These scales are the “dust” you will find on your finger and thumb if ever you pick up a butterfly in such an unscientific manner. You will notice, too, that the under sides of the wings bear quite a different design from the upper sides; this is nearly always the case, and in many foreign butterflies this difference between the two sides is so very remarkable as to be quite startling in its effect. Well I remember an old sergeant-major, who had spent many years in India, and had done a lot of “butterfly dodging” in his day, telling me of this wonderful effect. He said one would come upon an open piece of meadow-land blazing with flowers and butterflies, but, on being disturbed, the whole crowd of insects would rise in the air, and then, he would say, they looked like a different set altogether. When you capture a few specimens of any species, examine closely the under sides, and in any case, if you wish to preserve them, always set one of each sex with the under side uppermost.

Next to the wings the head claims our attention; it supports three very essential organs—the eyes, the horns, or antennæ, and the tongue, or sucker.

The antennæ are undoubtedly the organs of smell, which is perhaps the most highly developed sense in the Insect World. That the eyes are a marvel of beauty, and that the tongue is a finely finished little instrument for its work no one can question; but the sense of smell has a much longer range than even the eye, with all its facets. And you will generally find, in relation to the faculty which any animal or insect has to exert most so as to procure its food and propagate its kind, the organ of that faculty reaches the highest point of development and service.

The eyes of the condor and the gannet must be marvellous in range and penetrating power. I have watched scores of the latter birds sailing and hovering 150 feet and more above a troubled sea. Suddenly there would be a slight pause, and then a rocket-like dive right down into the waves below. To see a fish on the surface from such a height would be a great feat, but to see and catch one a dozen feet deep in a broken sea as a gannet can do, is wonderful indeed.

With butterfly and moth the sense of smell is of the greatest importance. Their vision is good, but short in range; so to find the flowers wherein lies their food the sight is good, but the power to detect them by scent must be far better. “Over the hedge is a garden fair,” and if a butterfly cannot see through the hedge, he can at least smell through it. He could fly over it? Yes, but if his sense of smell says there is nothing there for him, you see he is saved the time and trouble; and his life is short.

“Assembling” and “treacling” for moths are two methods employed by insect-hunters to secure an abundance of specimens otherwise difficult to obtain, and in both cases it is this same wonderful sense of smell which is the insect’s undoing.

For “assembling,” a captive virgin female is taken at dusk to the locality where the species is likely to occur, and if males are about they very soon make their appearance. The female being in a gauze-covered box, they will swarm over it in their efforts to find an entrance, and when thus engaged can be easily captured. As for the subtle odour emitted by the lady, you or I could never detect it, yet these moths come swarming from far and near. I once witnessed a curious phase of this instinct on a hillside in Arran. My attention was arrested by a number of males of Bombyx Quercus (variety, Callunæ), keeping near and flying over a certain spot, and, thinking a female might be about, I went over to investigate. It was a female, but a dead and crushed one; how it had met its end I could only conjecture; but evidently, although the insect was mutilated, the scent still lingered, and brought the males circling round. This large moth flies boldly during the day, and in Arran the larvæ feed on the heather.