Possibly I may not have brought up my larva with the wholesome frugality which the mother would have shown; there may have been some waste in the daily rations, provided all at once and left entirely to the discretion of the grub. I fancied that in some particulars things did not go on exactly as in the cell, for my notes have such details as: “In the alluvial sands of the Durance I discovered a burrow into which Bembex oculata had taken a Sarcophaga agricola. At the bottom of the gallery was a larva, numerous fragments, and some Diptera entire—namely, four Sphærophoria scripta, one Onesia viarum, and two Sarcophaga agricola, counting that which the Bembex had brought under my very eyes.” Now it must be remarked that one half of this game, the Sphærophoria, was quite at the bottom of the cell—under the very jaws of the larva, while the other half was still in the gallery—on the threshold of the cell—consequently out of the grub’s reach, as it could not leave its place. It would seem that when game abounds, the mother disposes provisionally of her captures on the threshold of the cell, and forms a reserve on which she draws as need arises, especially on rainy days, when all labour is at a standstill. This economy in distributing food would prevent the waste unavoidable with my larva perhaps too sumptuously treated. I subtract then from the sum obtained, and reduce it to sixty pieces of medium size, between that of the house-fly and Eristalis tenax. This would be about the number of Diptera given by the mother to the larva when the prey is middle-sized, as is the case with all the Bembecids of my district except B. rostrata and B. bidentata, which especially favour the gadfly. For these the number of slain would be from one to two dozen, according to the size of the Dipteron, which varies greatly in the gadfly species. In order not to return to the kind of provisions, I give a list of the Diptera observed in the burrows of the six kinds of Bembex, which are the subject of this essay. (1) B. olivacea, Rossi. Once only have I seen this species, at Cavaillon, preying on Lucilia Cæsar. The five next are common round Avignon. (2) B. oculata, Jur. The Dipteron upon which the egg is laid is generally a Sphærophoria, especially S. scripta; sometimes it is a Geron gibbosus. Further provender consisted in Stomoxys calcitrans, Pollenia ruficollis, P. rudis, Pipiza nigripes, Syrphus corollæ, Onesia viarum, Calliphora vomitoria, Echinomyia intermedia, Sarcophaga agricola, Musca domestica. The usual food was Stomoxys calcitrans, of which I have found fifty or sixty in a single burrow. (3) Bembex tarsata, Lat. It, too, lays its egg on Sphærophoria scripta; but it also hunts Anthrax flava, Bombylius nitidulus, Eristalis æneus, E. sepulchralis, Merodon spinipes, Syrphus corollæ, Helophilus trivittatus, Zodion notatum. Its favourite prey consists in Bombylius and Anthrax.