The species of the genus Sphex are fairly numerous, but are for the most part strangers to my country. As far as I know, the French fauna numbers only three, all lovers of the hot sun of the olive district, namely, the Yellow-winged Sphex (Sphex flavipennis), the White-edged Sphex (S. albisecta), and the Languedocian Sphex (S. occitanica). Now it is not without a lively interest that the observer notices in the case of these three freebooters a choice of provisions which is in strict accordance with the rigid laws of entomological classification. To feed their grubs, all three choose solely Orthoptera. [25] The first hunts Crickets, the second Locusts, the third Ephippigers. The prey selected have such great outward differences one from the other that to associate them and grasp their similarity calls for the practised eye of the entomologist or the no less experienced eye of the Sphex. Pray compare the Cricket with the Locust: the first has a large, round, stumpy head, is short and thickset and black all over, with red stripes on his hinder thighs; the second is greyish in colour, long and slim, with a small, tapering head, leaps forward by suddenly unbending his long hind-legs and continues this flight with wings furled like a fan. Next compare both of these with the Ephippiger, who carries his musical instrument, two shrill cymbals shaped like concave scales, on his back and who waddles along with his pendulous belly, ringed pale-green and buttercup-yellow and armed with a long dirk. Place the three side by side and you will agree with me that, to guide her in choosing between such dissimilar species, while still keeping to the same entomological order, the Sphex must have an eye so expert that no man—not your ordinary layman, but a man of science—need be ashamed to own it. In the face of these singular predilections, which seem to have had their limits laid down for them by some master of classification, by a Latreille, for instance, it becomes interesting to investigate whether the Sphex-wasps that are not natives of our country hunt game of the same order. Unfortunately, information on this point is scanty and, in the case of most of the species, is lacking altogether. The chief cause of this regrettable lacuna is the superficial method generally adopted. People catch an insect, stick a long pin through it, fix it in the cork-bottomed box, gum a label with a Latin name underneath its feet, and let its history end there. It is not thus that I understand the duties of an entomological biographer. It is no use telling me that this or that species has so many joints to its antennæ, so many nervures to its wings, so many hairs on a region of the belly or thorax; I do not really know the insect until I am acquainted with its manner of life, its instincts and its habits.