Romanes[31] thought that the manner of stinging and paralyzing their prey might “be justly deemed the most remarkable instinct in the world.” Spiders, insects, and caterpillars are stung, he says, “in their chief nerve-centres, in consequence of which the victims are not killed outright, but rendered motionless; they are then conveyed to a burrow and, continuing to live in their paralyzed condition for several weeks, are then available as food for the larvæ when these are hatched. Of course the extraordinary fact which stands to be explained is that of the precise anatomical, not to say also physiological knowledge which appears to be displayed by the insect in stinging only the nerve-centres of its prey.” Eimer[32] thought that it “is absolutely impossible that the animal has arrived at its habit otherwise than by reflection upon the facts of experience.” “At the beginning,” he says, “she probably killed larvæ by stinging them anywhere, and then placed them in the cell. The bad results of this showed themselves; the larvæ putrified before they could serve as food for the larval wasps. In the mean time the mother wasp discovered that those larvæ which she had stung in particular parts of the body were motionless but still alive, and then she concluded that larvæ stung in this particular way could be kept for a longer time unchanged as living motionless food.” Now, since these wasps, when they have stored their nests and laid an egg on one of the victims, close it up once and for all, and take no further interest in it or its contents, there seems no opportunity, at any rate in the existing state of matters, for the acquisition of that experience on which Eimer relied. But both his explanation and Romanes’s difficulty are based on the following assumptions: first, that the victims are instinctively or habitually stung in the chief nerve-centres; secondly, that when thus stung they are not killed but remain paralyzed for weeks; and thirdly, that the marvellously definite and delicate instinctive behaviour is in direct relation to the uniform result of prolonged paralysis and consequent preservation of the food in the fresh state. But Dr. Peckham’s careful observations and experiments show that, with the American wasps, the victims stored in the nests are quite as often dead as alive; that those which are only paralyzed live for a varying number of days, some more, some less; that wasp larvæ thrive just as well on dead victims, sometimes dried-up, sometimes undergoing decomposition, as on living and paralyzed prey; that the nerve-centres are not stung with the supposed uniformity; and that in some cases paralysis, in others death, follows when the victims are stung in parts far removed from any nerve-centre. “We believe,” he says, “that the primary purpose of the stinging is to overcome resistance, and to prevent the escape of the victims, and that incidentally some of them are killed and others are paralyzed.”