Let us add that in other circumstances I have repeatedly found this Hymenopteron, I suppose to be a parasite—this Tachytes nigra, dragging a cricket by one of its antennæ. Was it a prey lawfully acquired? I would fain think so, but the indecision of the insect which strayed about the ruts in the paths as if seeking a convenient burrow always left me suspicious. I have never been present when it burrowed, if indeed it ever does undertake that labour, and what is more, I have seen it abandon its game to decay, perhaps not knowing what to do with it for want of a hole where to put it. Such wastefulness seems to indicate goods ill-gotten, and I ask myself if the cricket were not stolen when the Sphex left it on her threshold? I also suspect Tachytes obsoleta, banded with white round the abdomen like Sphex albisecta, which nourishes its larvæ with crickets such as are hunted by the latter. I have never seen it digging galleries, but I have caught it dragging crickets that the Sphex would not have disdained. This similarity of food in species of different genera makes me doubtful whether the booty were lawfully come by. Let me add, however, to atone in some measure for the injury which my suspicions may do to the character of the genus, that I have seen the perfectly lawful capture of a little cricket yet wingless by Tachytes tarsina, and have also seen it hollow cells and store them with prey bravely acquired. Thus I have only suspicions to offer as to why the Sphex persists in descending to the bottom of her hole before carrying in prey. Is there some other end besides that of dislodging a parasite which may have got in during the owner’s absence? I despair of finding out; who can interpret the thousand manœuvres of instinct? Poor human reason which cannot even explain the wisdom of a Sphex! At all events, it is proved that these manœuvres are singularly invariable, àpropos of which I will mention an experiment which greatly interested me. At the moment when the Sphex makes her domiciliary visit, I take the cricket and put it some way off. The Sphex comes up, utters her usual cry, looks round with astonishment, and seeing the game too far off, comes out to seize and put it in the right position. Then she goes down again without the cricket. Same manœuvre on my part, same disappointment when she reappears. Again the prey is brought to the mouth of the hole, and again the Sphex goes down alone, and so on as long as my patience holds out. Forty times on end have I tried the experiment on the same individual; her persistence vanquished mine, and her tactics never varied.