It appears from what precedes that the social life is found in very different groups and with groups which are very diverse from the psychic point of view. This form of life is, then, equally independent of heredity and of intelligence. As Lameere1 judiciously observes, the origin of these societies "results from ethological factors which bring organisms of the same species together in the same locality, leading up to the establishment of social ties." The ethological factors, the conditions of the environment favorable to the parents, are equally favorable to their descendants, who, because of the law of least effort, do not fail to profit by it provided the space is sufficient and that the habits of the animal are such that an individual permits or desires the neighborhood of its kin. And that shows us that combinations or groups of individuals are already family groups; also, that strangers of the same species can profit by the conditions of the favorable environment to join themselves to these groups and to enlarge them. From this a colony will develop which to a certain degree will differ from an adjoining one in its habits, from the fact that it represents a different family grouping. It is in this way that Fabre has interpreted his curious observations upon the ineptness which is characteristic of the yellow-winged sphex in certain of its colonies and upon the cleverness with which it meets emergencies in certain others (see page 114). The factors of the communistic social life. Although we observe all intergrades between individualistic societies and communistic societies, the primordial trait of the latter is the association of the young with their parents in a manner which is profitable to both. In order that such a group shall be possible, it is necessary that the young, at least the first young, see the day while their parents are still working on the nest; but this condition is not enough ; besides this, it is necessary that the young should belong to a species which is more or less sociable.

1 R. du Buysson, Monographie des Guêpes ou Vespa, 1903. (Ann. Soc. Ent. France, v. 72, pp. 260-882).

1. Lameere, L'Origine des Sociétés d' Insectes, 1915. {Rev. gén. des sci. pures et appliv. v. 26, pp. 459-464).

We know from Fabre that the female of Copris hispanicus remains in the burrow near its egg and even helps the young in hatching, but the latter when once out do not associate with their mother, for Copris prefers to work alone. It is probably not the same with Halictus quadrimaculatus studied by Verhoeff and with the Synagris studied by Eoubaud, for the first young of these social Hymenoptera remain in contact with their parents. But the phenomenon is rare, if it occurs, and it is not known in any communistic society among these insects. With these, however, we are on the point of beginning the evolution of the social life. When, with species possessing similar instincts, the hatchings are such that normally there is contact between the parents and their young, the latter do not migrate. And if they remain in the nest in which they were born, "it is probably," as Lameere says, "by virtue of the law of the least effort:-they profit by the work begun by their parents or by their mother," and that is, in fact, what we s,ee in all communistic societies.