First and foremost the old English savant ought to have known enough about the creatures which he so freely ennobles to call things by their right name. Let us therefore take the word Sphex in its strictly scientific sense. Then by what strange aberration does this English Sphex, if English ones there are, choose a fly as its prey when its fellows hunt such different game—namely, Orthoptera? And even if we grant, what I consider inadmissible, a Sphex catching flies, other difficulties crowd in. It is now proved on evidence that the burrowing Hymenoptera do not carry dead bodies to their larvæ, but merely prey benumbed and paralysed. What, then, is the meaning of this prey whose head, abdomen, and wings are cut off? The torso carried away is but a portion of a corpse that would infect the cell and be useless to the larva, not yet to be hatched for several days. It is perfectly clear that Darwin’s insect was not a Sphex, strictly speaking. What, then, did he see? The word fly, by which the captured prey is designated, is a very vague term which might be applied to the greater part of the immense order of Diptera, and therefore leaves us uncertain among thousands of species. Probably the name of Sphex is used equally vaguely. When Darwin’s book appeared, not only the real Sphegidæ were so called, but also the Crabronides. Now among these last some provide their larvæ with Diptera, the prey required for the unknown Hymenopteron of the English naturalist. Was then Darwin’s Sphex a Crabro? No, for these hunters of Diptera, like the hunters of any other game, require prey which will keep fresh and motionless, but half alive for the fortnight or three weeks needed before the eggs hatch, and for the complete development of the larvæ. These little ogres require meat not decayed, nor even high, but fresh. I know no exception to this rule, and therefore the name Sphex cannot have been used in its old meaning.