All moths with highly pectinated antennæ, that is to say with their feelers comb-like at the extremities, have the most extraordinary power of scenting a female moth at a great distance, even two or three miles, with a favourable wind.
Mr. Bignell says: "I once had a virgin female of the Oak-egger moth, and was desirous of getting some males. I started off with the lady in a tin box, with a perforated zinc top, to give her air and allow her perfume to escape. I walked through the fields towards Milehouse to where was a turnstile; and at this spot lighted on a weary policeman resting. As it was a dull day, without any token of the sun breaking out, to attract butterflies for their usual gambols, the policeman jeeringly remarked that I had missed the right day. I replied that I thought not, and that I could collect as many as I desired, in fact, I could make them come to me. He laughed incredulously. I then took out my tin box and placed it on the wall, and, magician-like, whistled and waved my hand. The policeman stared, and thought I was befooling him. But lo, in two or three minutes one male alighted close to the box, soon followed by others, and in a quarter of an hour I had at least fifty, and so tame that I picked them up with my fingers and distributed them among about a dozen people who had gathered to see what I was about. The policeman stared with open eyes and mouth, quite satisfied that my whistle and mysterious signs in the air with my hand had called the insects to me. Satisfied with what I had got I waved again and bade the moths depart, and clapped the box in my pocket. Next day I took the empty box out with me into the country. I had several males following me, and some actually penetrated into my pocket where was the empty box, proving that the perfume still remained in it, though wholly imperceptible to myself."
On one occasion Mr. Bignell and a friend set out at night to find the beautiful moth Heliophobus hispidus, knowing its haunts, between the south side of the Plymouth citadel and the sea, where it is to be found in September or October resting on the grass.
Accordingly, each furnished with a bull's-eye lantern, they visited the locality, but it was some time before one was discerned, and that was on a blade of grass overhanging the cliff and out of reach, a sheer drop of twenty feet at least into the sea fretting and moaning below. Loath to miss it, as its eyes shone like two rubies—in fact, both saw those glistening eyes before they observed that they were in the head of the moth—they arranged that one should lie flat on his stomach, and that Mr. Bignell should sit down, dig the heels of his boots into the turf, then take his friend by the legs and thrust him over the edge of the cliff, so far as to enable him to box the moth, whilst holding the handle of his lantern between his teeth. This was done, and the Heliophobus was secured.
But, after all, it is in the direction of parasites living upon insects that Mr. Bignell has made the greatest research. He is the possessor of a unique collection of the parasites that live on the aphis, and also of the hyper-parasite which preys upon that parasite. The life-history of this insect was unknown till Mr. Bignell detected a hyper-parasite pierce the aphis which was itself a parasite. The specimen was secured, and from it was bred the hyper-parasite itself.
The life-story of the aphis, that tiny green pest that infests the roses, has been unrolled by this enthusiastic student, and is full of surprises. The ichneumon fly as well has been watched, and all its wicked acts recorded.
Caterpillars, so fat and fleshy, form a delightful feeding ground for the deposit of eggs, and serve as luscious food for the young to pasture upon. We human beings, in common with all mammals, have the obligation imposed on us of nourishing our own young, and with some of us we go on sustaining them till we are exhausted in the process, but the ichneumonidæ are more clever than we. They make others, notably the caterpillars, maintain their young, and the frivolous mothers, after having once deposited their eggs, gad about and enjoy themselves as having no concern for their future well-being. It is a comfort to reflect that the insects thus preyed upon do not seem to suffer much, if at all, and it may almost be said that they exhibit a maternal regard for the young bred out of their bodies.
With his wonderful microscopes Mr. Bignell can explore far down the ladder of life, but whether to its lowest rung may well be doubted. There is always some living being to be found preying on the last of the minutest creature last seen.
After a visit to Mr. Bignell's house in Saltash with a friend, I turned to him and said: "I came here believing myself to be an Individual. I leave knowing myself to be a Community."