It is possible that I did not rear my larva with the wholesome frugality and the wise economy which the mother would have shown; there was perhaps some waste in the daily provisions served all at one time and left entirely to the grub’s discretion. In some respects I feel inclined to believe that things do not happen just like that in the maternal cell, for my notes contain such details as the following. In the alluvial sands of the Durance I discover a burrow which the Wasp (Bembex oculata) has just entered with a Sarcophaga agricola. Inside I find a larva, numerous fragments and a few whole Flies, namely, four Sphærophoria scripta, one Onesia viarum and two Sarcophaga agricola, including the one which the Bembex has just brought along before my eyes. Now it is worthy of remark that half of this game, namely, the Sphærophoriæ, is right at the end of the cell, under the larva’s very teeth, whereas the other half is still in the passage, on the threshold of the cell, and therefore beyond the reach of the grub, which is unable to change its position. It seems to me then that, when game is plentiful, the mother lays her captures on the threshold of the cell for the time and forms a reserve on which she draws as and when necessary, especially on rainy days when all labour is at a standstill. Thus practised with economy, the distribution of food would save a waste which I was not able to prevent with my larva, treated I dare say too sumptuously. I therefore lower the figure obtained and reduce it to some sixty pieces, of middling size, between that of the House-fly and of the Eristalis tenax. This would about represent the number of Flies supplied by the mother to the larva when the prey is of a moderate size, as is the case with all the Bembex of my district except the Rostrate Bembex (B. rostrata) and the Two-pronged Bembex (B. bidentata), who have a preference for Gad-flies. With them, the number of victims would be from one to two dozen, according to the size of the Fly, which varies greatly in the different species of Gad-flies. To avoid reopening this question of the nature of the provisions, I will here give a list of the Flies observed in the burrows of the six species of Bembex that form the subject of this essay. 1. Bembex olivacea, Rossi. I only once saw this species, at Cavaillon, feeding on Green-bottles. The five other species are common in the Avignon neighbourhood. 2. Bembex oculata, Jur. The Fly carrying the egg is most often a Sphærophoria, especially S. scripta; sometimes it is a Geron gibbosus. The later provisions include Stomoxys calcitrans, Pollenia ruficollis, P. rudis, Pipiza nigripes, Syrphus corollæ, Onesia viarum, Calliphora vomitoria, [37] Echinomyia intermedia, Sarcophaga agricola and Musca domestica. [38] The usual fare consists of Stomoxys calcitrans, of which I have many a time found fifty or sixty in a single burrow.