If we throw a spider that has been stung by a fellow-wasp at one of these, it will nearly always be taken without hesitation, and will often be stung again. The depositing and the laying of the egg are done as if by habit; and I may add that the hunter is not dainty as to the freshness of his game. I have seen spiders of eight days' standing accepted, and have repeated the experiment so often that I can not suppose that the fact is accidental. It is not a case of one opening a cell to deposit an egg because its own has been stolen, or of digging into the partitions at the end of its labors; but what I relate happens almost regularly whenever occasion offers. It may be said that the insect is obliged to deposit its egg. Perhaps, but the necessity for ovipositing is singularly elastic with my pompili, and is associated with the faculty they have of stealing the game of their neighbor.
A Pompilus viaticus has just drawn its spider into the cell. It has deposited its egg and stopped up its hole. I offer it a new spider, killed; it is not the time for ovipositing, but the victim is accepted and placed carefully by the side of the nest, the closing of which is arrested. A new cell is dug out, the booty is drawn into it, and receives an egg in its turn.
I have often repeated this experiment with Pompilus viaticus and pectinipes. I broke open the half-closed nest, and unfastened the egg, and I have several times seen the spider taken up, carried a little farther on, and the ovipositing begun again.
So far I have told of experiments; now I come to pure observation. Let us go at the beginning of September into a warm gravelly quarry. We see many hymenoptera there, but the pompilides dominate. They have chosen the most agreeable quarter, the most sunny one in the city. Those which I observed were the Pompilus rufipes. They are a colony of crafty fellows, constantly in motion, ferreting everywhere, sometimes on the quest for a neighbor's spider, going into the holes which they find to their taste to drive the proprietors from them. When they have succeeded in stealing, they bury their spoil, if some other thief does not interfere, and deposit an egg upon it. These thefts are often the occasion of lively combats. I chanced to see two of the largest of the band disputing over a spider. Hunters and victim rolled like a ball along the gravel for four or five yards. The contestants, which had not let go, tugged at their prey like dogs wrangling over a bone. After a few minutes the beaten one—generally the less corpulent—gave up the struggle. The species, however, is not parasitic. The spider is in the beginning the legitimate prey of one of the two, and I have, besides, seen them hunting and ovipositing honestly in the same quarry.
Not only in the capture of the prey, but in the choice of the
