On various occasions about the end of April the gardens afford me the sight of such processions, sometimes longer, sometimes shorter. I capture them and place them in the vivarium. Bloodshed commences the moment the banquet is served. The caterpillars are eviscerated; each by a single beetle, or by several simultaneously. In less than fifteen minutes the flock is completely exterminated. Nothing remains but a few shapeless fragments, which are carried hither and thither, to be consumed at leisure under the shelter of the wooden board. One well-fed beetle decamps, his booty in his jaws, hoping to finish his feast in peace. He is met by companions who are attracted by the morsel hanging from the mandibles of the fugitive, and audaciously attempt to rob him. First two, then three, they all endeavour to deprive the legitimate owner of his prize. Each seizes the fragment, tugs at it, commences to swallow it without further ado. There is no actual battle; no violent assaults, as in the case of dogs disputing a bone. Their efforts are confined to the attempted theft. If the legitimate owner retains his hold they consume his booty in common, mandibles to mandibles, until the fragment is torn or bitten through, and each retires with his mouthful.
As I found to my cost in bygone experiments, the pine-caterpillar wields a violently corrosive poison, which produces a painful rash upon the hands. It must therefore, one would think, form a somewhat highly seasoned diet. The beetles, however, delight in it. No matter how many flocks I provide them with, they are all consumed. But no one, that I know of, has ever found the Golden Gardener and its larva in the silken cocoons of the Bombyx. I do not expect ever to make such a discovery. These cocoons are inhabited only in winter, when the Gardener is indifferent to food, and lies torpid in the earth. In April, however, when the processions of larvæ are seeking a suitable site for burial and metamorphosis, the Gardener should profit largely by its good fortune should it by any chance encounter them.
The furry nature of the victim does not in the least incommode the beetle; but the hairiest of all our caterpillars, the Hedgehog Caterpillar, with its undulating mane, partly red and partly black, does seem to be too much for the beetle. Day after day it wanders about the vivarium in company with the assassins. The latter apparently ignore its presence. From time to time one of them will halt, stroll round the hairy creature, examine it, and try to penetrate the tangled fleece. Immediately repulsed by the long, dense palisade of hairs, he retires without inflicting a wound, and the caterpillar proceeds upon its way with undulating mane, in pride and security.
But this state of things cannot last. In a hungry moment, emboldened moreover by the presence of his fellows, the cowardly creature decides upon a serious attack. There are four of them; they industriously attack the caterpillar, which finally succumbs, assaulted before and behind. It is eviscerated and swallowed as greedily as though it were a defenceless grub.
According to the hazard of discovery, I provision my menagerie with various caterpillars, some smooth and others hairy. All are accepted with the utmost eagerness, so long as they are of average size as compared with the beetles themselves. If too small they are despised, as they would not yield a sufficient mouthful. If they are too large the beetle is unable to handle them. The caterpillars of the Sphinx moth and the Great Peacock moth, for example, would fall an easy prey to the beetle were it not that at the first bite of the assailant the intended victim, by a contortion of its powerful flanks, sends the former flying. After several attacks, all of which end by the beetle being flung back to some considerable distance, the insect regretfully abandons his prey. I have kept two strong and lively caterpillars for a fortnight in the cage of my golden beetles, and nothing more serious occurred. The trick of the suddenly extended posterior was too much for the ferocious mandibles.
The chief utility of the Golden Gardener lies in its extermination of all caterpillars that are not too powerful to attack. It has one limitation, however: it is not a climber. It hunts on the ground; never in the foliage overhead. I have never seen it exploring the twigs of even the smallest of bushes. When caged it pays no attention to the most enticing caterpillars if the latter take refuge in a tuft of thyme, at a few inches above the ground. This is a great pity. If only the beetle could climb how rapidly three or four would rid our cabbages of that grievous pest, the larva of the white cabbage butterfly! Alas! the best have always some failing, some vice.
To exterminate caterpillars: that is the true vocation of the Golden Gardener. It is annoying that it can give us but little or no assistance in ridding us of another plague of the kitchen-garden: the snail. The slime of the snail is offensive to the beetle; it is safe from the latter unless crippled, half crushed, or projecting from the shell. Its relatives, however, do not share this dislike. The horny Procrustes, the great Scarabicus, entirely black and larger than the Carabus, attacks the snail most valiantly, and empties its shell to the bottom, in spite of the desperate secretion of slime. It is a pity that the Procrustes is not more frequently found in our gardens; it would be an excellent gardener's assistant.