We remark that this devotion to the public weal is like society in its beginning. It is less developed here than among the wasps and the honeybees. Near the one who died so bravely on the field of honor, I saw a new halictus alight in front of the enemy at the first attack to go take care of the dying. Honeybees do not hesitate when their city is to be defended, and bumblebees, Hoffer says, often precipitate themselves upon the man who is destroying their nest; but their civilization, if I may use the word, is much more advanced than that of the halictus. Courage and abnegation are therefore not only the appanage of mankind or of rich societies of honeybees and ants; they belong to every association—to all those, whether beasts or people, who bind their hearts together in the struggle for existence.
The tenacity of the sphœcodes on the field of battle is not less surprising; it is, so far as I know, the only example of a parasite issuing from the peaceful progeny of the apiaries that gives battle for the acquisition of spoil.
Have we here a species of parasite in course of formation? I do not know. There is a great distance between the sphœcode and the halictus. The variation of the genus or species sphœcodes is very great, it is true; but that of the bumblebees is of the same order, and there are fossil bumble bees. The hazardous life of the parasite should teach us reserve concerning the cause of its variations.
I believe we may observe a nascent parasitism in another family of Hymenoptera. I mean among those insects which honestly gain life for their young most of the time, but which also do not disdain to rob a neighbor, to play the parasite, and that not fortuitously, but almost every time an occasion presents itself. I have found such insects in the spider-killing family of the Pompilidœ.
The pompiledes are those little black wasps, with a somewhat party-colored abdomen, which may be seen lingering on sunny talus or walls, with their antennae and wings in febrile vibration. Those that I have observed in France and Algeria chase spiders. They pursue them, keeping in touch with the ground like a dog following game. The manner of attack varies with the species of the hunters. Nearly all those that I have seen light directly upon the enemy, which rolls over, and stab it. The spider is generally put in a safe place on top of a tuft or a stone, while the pompilus digs a hole in which it deposits the anæsthetized head, after gluing its egg upon the abdomen. The pompilides are not all diggers—some choose or prepare the most singular places for their progeny; but the general rule is as I have described it.
My observations have been made chiefly upon the Pompilus viaticus (Latreille) and on the Pompilus rufipes (Vanderlinden).
