I still ask myself, without being able to find a sufficiently convincing solution, the reason for these complicated proceedings at the moment when the Cricket is introduced into the burrow. Instead of going down to her den alone, to reappear afterwards and pick up the prey left for a time on the threshold, would not the Sphex have done better to continue to drag the Cricket along the gallery as she does in the open air, seeing that the width of the tunnel permits it, or else to go in first, backwards, and pull him after her? The various Predatory Wasps whom I have hitherto been able to observe carry down to their cells straight away, without preliminaries, the game which they hold clasped beneath their bellies with the aid of their mandibles and their middle-legs. Léon Dufour’s Cerceris begins by complicating her procedure, because, after laying her Buprestis for a moment at the door of her underground home, she at once enters her gallery backwards and then seizes the victim with her mandibles and drags it to the bottom of the burrow. But it is a far cry from these tactics and those adopted in a like case by the Cricket-hunters. Why that domiciliary visit which invariably precedes the entrance of the game? Could it not be that, before descending with a cumbrous burden, the Sphex thinks it wise to take a look at the bottom of her dwelling, so as to make sure that all is well and, if necessary, to drive out some brazen parasite who may have slipped in during her absence? If so, who is the parasite? Several Diptera, Predatory Gnats, especially Tachinæ, watch at the doors of the Hunting Wasps, spying for the propitious moment to lay their eggs on others’ provisions; but none of them enters the home or ventures into the dark passages where the owner, if by ill-luck she happened to be in, would perhaps make them pay dearly for their audacity. The Sphex, like all the rest, pays her tribute to the plundering Tachinæ; but these never enter the burrow to perpetrate their misdeeds. Besides, have they not all the time that they need to lay their eggs on the Cricket? If they are sharp about it, they can easily profit by the temporary abandonment of the victim to entrust their progeny to it. Some greater danger still must therefore threaten the Sphex, since her preliminary descent of the burrow is of such imperious necessity.