These and _Apis mellifica_ are our only social bees, which live in numerous communities under a kind of municipal government which is considerably less perfectly organized in the present genus than in the domestic bee, and thence they are called “villagers,” in contradistinction to the citizenship of the hive bee, earned by its comparatively metropolitan institutions, and the centralization of its government, which wholly emanates from the pervading influence of the queen upon the labours, and, indeed, upon the existence of her subjects. But the _Bombi_ are under much less social restraint, and admit of several co-regents in the same community, without its being productive of any disturbance of social harmony. In the account of the genus _Apathus_, the last described, we have seen that the _Bombi_ are subject to bee-parasites, which in some closely resemble the species they infest, and we have also shown there how these are distributed. The hive bee is not exposed to such intrusion, although, like these, they have many enemies. In the very earliest spring months these _Bombi_ are abroad; for as soon as the catkins of the sallow are ripe for impregnation, they are on the wing. But it is now that the large females only are at work, for they have to create their companions before they can be surrounded by them. Their fruition is the result of the previous autumn’s amours, at a period too late to form sufficient stores for the numerous brood they will produce, and accordingly, after revelling in a brief honeymoon, they resort, like staid matrons, to a temporary domicile, some cavity just large enough for themselves. In this retirement they pass the cheerless wintry months, requiring perhaps the incubation of time thoroughly to mature their fruit. Whether this be the case or not, as soon as the earth begins to feel the warmth of the sun upon its return from its far southern journey, and to respond to the renewed vitality it gives to vegetation, these bees feel its active influence and come forth. With the progress of the spring and summer most flowers are exposed to their rifling, but they revel upon the elegant flowers of the Horse-chestnut, and their hum is the music of the lime when it is in blossom. According to the species, they select a cavity for their nest, or construct it upon the surface of the ground, this being the case with the CARDER-BEES, which gather moss to construct their residence. In those which inhabit beneath the surface, the selection of an already formed cavity greatly abridges their labour, and their instinct prompts them to choose one sufficiently large for the prospective community, but the nest itself is gradually extended in size suitable to their progressive increase in numbers. All that the parent female does at first is to form a receptacle sufficiently large for her first gatherings of pollen and honey, whereon to deposit her first eggs, and to form a waxen cruse or two to contain the honey requisite for the nest operations of keeping these masses moist enough for the nurture of the larvæ. The material of these pots although called wax is not properly so, but is an agglutination of collected vegetable matter, for it is not plastic to the fingers like wax, and it burns, leaving a carbonaceous residuum very attractive to moisture. The larvæ hatched from the eggs now deposited produce the first neuters, which spin a cocoon wherein they rapidly undergo their transformations. They are, in the first instance, aided to emerge from their silken cot by the parent gnawing off its top, but subsequently this duty is performed, as the family increases, by the neuters then developed. The young bee, on emerging from its cocoon, is not thoroughly hardened in its integument, and its pubescence also acquires by degrees only its proper colouring; all this is not long in being effected, but, until they are thoroughly able to fly forth, they continue to be fed by their elder sisterhood, for the neuters are properly abortive females. Males, and further productive females are produced later in the spring, and are smaller than the normal sizes of those sexes; the autumnal brood, consisting also of males and females, again resume the full size of the complete insect, and it is these females which, after impregnation, hibernate and reappear in the following early spring to be each the parent of a new progeny. The population of these nests varies considerably in the several species: in some, as in that of _Bombus terrestris_, there are more than two hundred, and in that of _B. senilis_ there are about a hundred and forty; but it is in those that construct their nests above the ground that the fewest are found.