The larva, on its side, licks the base of its neck for a few seconds. There is here, at the moment when the grub is being served with food, a sort of projecting bib, a temporary dewlap which forms a porringer and receives what trickles from the lips. After swallowing the bulk of the ration, the larva finishes its meal by gathering up the crumbs which have fallen on its bib. Then the swelling disappears; and the grub, withdrawing a little way into its cell, resumes its sweet slumbers.
The better to watch this curious fashion of eating, I happen by good luck to have a few powerful Hornet-larvæ. I slip them singly into paper sheaths, which will represent their natal cells. Thus swaddled, my fat babies lend themselves excellently to observation when I myself distribute their rations.
In my young days, we had a trick of tapping [[275]]with our finger the incipient tail of the Sparrow whom we were rearing. The pupil at once yawned, ready to receive his food. I like to imagine that this system of bird-training is still in vogue. But there is no need of these stimulating preliminaries to arouse the appetite of the Hornet’s offspring. They yawn of their own accord at the least touch that I give to their cell. The lucky creatures have ever-ready stomachs.
Taking a piece of straw with a drop of honey hanging from it, I place the delicious ration between the grub’s mandibles. There is too much for a single mouthful. But the breast swells into a dewlap which catches the surplus. Here the grub will take a few more sips, at its leisure, after swallowing the spoonful which it received direct. When there is no more left, when the pectoral platter is licked clean, the swelling disappears and the larva resumes its immobility. Thanks to this short-lived swelling, suddenly flung out and as suddenly withdrawn, the diner has its table spread beneath its chin; without assistance from others, it finishes its meal alone.
When fed in my cage, the Wasps’ grubs have their heads up; and what escapes their lips collects upon the dewlap. When fed [[276]]normally, in the Wasps’-nest, they have their heads down. In this position is the protuberance on the breast of any service? I cannot doubt it.
By slightly bending its head, the larva can always deposit on its projecting bib a portion of the copious mouthful, which adheres to it by reason of its stickiness. Further, there is nothing to tell us that the nurse does not herself deposit the surplus of her helping on this spot. Whether it be above or below the mouth, right way up or upside down, the pectoral porringer fulfils its office because of the sticky nature of the food. It is a temporary saucer which shortens the work of serving and enables the grub to feed in a more or less leisurely fashion and without too much gluttony.
In the cage my Wasps are fed with honey, which they disgorge for the larvæ, once their crops are full. Both nurses and nurselings seem to thrive on this diet. Nevertheless, I know that the usual food is game. I have described elsewhere the hunting of the Eristalis by the Common Wasp and of the Hive-bee by the Hornet.[1] The moment she is caught, the big Fly in particular is dismembered; [[277]]the head, wings, legs and belly, those meagre portions, are cut off with snips of the shears. There remains the breast, which is rich in muscular tissues. This is the booty which, minced small upon the spot and reduced to a pill, is carried to the nest as a feast for the larvæ.
To honey, therefore, let us add game. I slip a few Eristales under the wire dome. At first the newcomers are not molested. The turbulent Flies, fluttering, buzzing, butting their heads against the wire-gauze, create no sensation in the cage. The inmates take no notice of them. If one of them pass too near to a Wasp, the Wasp just raises her head, as though in threat. That is quite enough; the Fly decamps.
Matters become more serious around the strip of paper covered with honey. The refectory is assiduously frequented by the Wasps. If the Eristalis, watching jealously from afar, venture to approach, one of the banqueters separates from the group, rushes headlong at the daring one, catches her by the leg and sends her to the right-about. The encounter is not really grave except when the Fly commits the imprudence of alighting on a comb. Then the Wasps fling themselves upon the hapless intruder, roll her over [[278]]and over, cuff her and drub her and drag her outside crippled or, as often as not, dead. The body is disdainfully rejected.
I renew my attempts in vain; I cannot reproduce the scenes which I used to witness on the aster-blossoms: the capture of the Eristalis and her reduction to mincemeat for the larvæ. Perhaps this strong animal fare is distributed only on certain occasions which are not realized in my cage; or perhaps—and I more incline to favour this idea—honey is judged to be better than meat. My prisoners have plenty of it, served up fresh daily. The nurselings thrive on this diet; and the salmis of Flies is rejected in consequence.