The Bembex are not the only victims of these parasites: all the Digger-wasps without distinction have their burrows plundered by Tachinæ and especially Miltogrammæ. Different observers, notably Lepeletier de Saint-Fargeau, have spoken of the wiles of these bold-faced Flies; but none of them, so far as I know, has remarked this very curious instance of parasitism at the expense of the Bembex. I say very curious, because the conditions are quite different. The nests of the other Digger-wasps are stocked beforehand and the Miltogramma drops her eggs on the pieces of game as they are taken in. When the Wasp has finished her catering and laid her egg, she closes the cell, where henceforth the lawful larva and the alien larvæ hatch and live together without ever being visited in their solitude. The mother therefore is not aware of the parasites’ brigandage, which remains unpunished because it is unknown. With the Bembex it is quite another matter. The mother is constantly returning indoors during the fortnight which it takes to rear her grubs; she knows that her offspring is living in the company of a number of intruders, who appropriate the best part of the food; each time that she brings provisions to her larva, she touches and feels at the bottom of the cavity those hungry guests who, far from contenting themselves with the remnants, seize upon the pick of the victuals; she must perceive, however limited her arithmetical faculties, that twelve are more than one; besides, the consumption of food, which is out of all proportion to her hunting powers, would tell her; and yet, instead of taking those presumptuous aliens by the skin of the belly and chucking them out of doors, she placidly tolerates them. Tolerates them, did I say? Why, she feeds them, she brings them provisions, having perhaps for those intruders the same affection as for her own larva! It is a new version of the story of the Cuckoo, but with even more singular circumstances. The theory that the Cuckoo, almost the size of the Sparrow-hawk and wearing the same dress, inspires enough respect to enable her to introduce her egg with impunity into the feeble Warbler’s nest, and that the latter, in her turn, perhaps over-awed by the fearsome appearance of her Toad-faced nurseling, accepts and looks after the stranger: this theory has some plausibility. But what should we say if the Warbler turned parasite and, with superb audacity, went and confided her eggs to the eyrie of the bird of prey, to the nest of the Sparrow-hawk himself, the bloodthirsty devourer of Warblers? What should we say if the rapacious Hawk accepted the trust and fondly reared the brood of little birds? And this is exactly what the Bembex does, that ravisher of Flies who tenderly nurses other Flies, that huntress who provides food for a quarry whose last meal will be made on her own disembowelled larva! I leave it to others, cleverer than myself, to interpret these astonishing relations.