None of the Bembex-wasps, whether chosen among the huntresses of the Gadfly or among the lovers of the House-fly rabble, satisfied my aspirations.
Their method is as unknown to me now as at the distant period when I used to watch it in the Bois des Issards. (Cf. "The Hunting Wasps": chapters 14to 18.--Translator's Note.) Their impetuous flight, their love of long journeys are incompatible with captivity. Stunned by colliding with the walls of their glass or wire-gauze prison, they all perish within twenty-four hours. Swifter in their movements and apparently satisfied with their honeyed thistle-heads, the Spheges, huntresses of Crickets or Ephippigers, die as quickly of nostalgia. All I offer them leaves them indifferent.
Nor can I get anything out of the Eumenes, notably the biggest of them, the builder of gravel cupolas, Amedeus' Eumenes. All the Pompili, except the Harlequin Calicurgus, refuse my Spiders. The Palarus, who preys upon an indefinite number of the Hymenopteron clan, refuses to tell me if she drinks the honey of the Bees, as does the Philanthus, or if she lets the others go without manipulating them to make them disgorge. The Tachytes do not vouchsafe their Locusts a glance; Stizus ruficornis promptly gives up the ghost, disdaining the Praying Mantis which I provide for her.
What is the use of continuing this list of checks? The rule may be gathered from these few examples: occasional successes and many failures. What can be the reason? With the exception of the Philanthus, tempted from time to time by a bumper of honey, the predatory Wasps do not hunt on their own account; they have their victualling-time, when the egg-laying is imminent, when the family calls for food. Outside these periods, the finest heads of game might well leave these nectar-bibbers indifferent. I am careful therefore, as far as possible, to capture my subjects at the proper season;I give preference to mothers caught upon the threshold of the burrow with their prey between their legs. This diligence of mine by no means always succeeds. There are demoralized insects which, once under glass, even after a brief delay, no longer care about the equivalent of their prize.
All the species do not perhaps pursue their game with the same ardour; mood and temperament are more variable even than conformation. To these factors, which are of the nicest order, we may add that of the hour, which is often unfavourable when the subject is caught at haphazard on the flowers, and we shall have more than enough to explain the frequency of the failures. After all, I must beware of representing my failures as the rule: what does not succeed one day may very well succeed another day, under different conditions. With perseverance and a little skill, any one who cares to continue these interesting studies will, I am sure, fill up many gaps. The problem is difficult but not impossible.
I will not quit my bell-jars without saying a word on the entomological tact of the captives when they decide to attack. One of the pluckiest of my subjects, the Hairy Ammophila, was not always provided with the hereditary dish of her family, the Grey Worm. I offered her indiscriminately any bare-skinned caterpillars that I chanced to find. Some were yellow, some green, some brown with white edges. All were accepted without hesitation, provided that they were of suitable size. Tasty game was recognized wonderfully under very dissimilar liveries. But a young Zeuzera-caterpillar, dug out of the branches of a lilac-tree, and a silkworm of small dimensions were definitely refused. The over-fed products of our silkworm-nurseries and the mystery-loving caterpillar which gnaws the inner wood of the lilac inspired her with suspicion and disgust, despite their bare skin, which favoured the sting, and their shape, which was similar to that of the victims accepted.
Another ardent huntress, the Interrupted Scolia, refused the Cetonia-grub, which is of like habits with the Anoxia-larva; the Two-banded Scolia also refused the Anoxia. The Philanthus, the headlong murderess of Bees, saw through my trickery when I confronted her with the Virgilian Bee, the Eristalis (E. tenax). She, a Philanthus, take this Fly for a Bee! What next! The popular idea is mistaken; antiquity too is mistaken, as witness the "Georgics," which make the putrid remains of a sacrificed Bull give birth to a swarm; but the Wasp makes no mistake. In her eyes, which see farther than ours, the Eristalis is an odious Dipteron, a lover of corruption, and nothing more.
