[Illustration: Figs. 336, 337, 338.--Anthophora parietina.] [Illustration: Fig. 339.--Carpenter Bee, Pupæ, Eggs, Galleries, and Nests.] The _Anthophoras_ (Figs. 336, 337, 338) resemble bees, but they are more hairy, and of greyish colour. Their nest, composed of earth tempered and agglutinated with their saliva, is made in the cracks of old walls or in the ground. It has the form of a twisted tube, and is divided, by partitions, into compartments, each of which is to receive a larva. Each insect, when hatched, pierces its own wall, and profits by the hole of exit of the brother which preceded it. [Illustration: Fig. 340.--Mason Bee and Nest.] These insects do not live together in societies. Indifferent neighbours, they do not lend each other mutual assistance. They have their parasites, the _Melactas_, like the humble bees. These parasites are hairy, blackish insects, spotted with white, laying their eggs in the nests of the _Anthophoras_, which permit them to do so, and, at the expense of their own progeny, bring up the intruder's little ones. The Carpenter Bee, or Wood-piercer (_Xylocopa_), hollows out galleries in decayed wood, and builds in them cells placed one over the other--a work often occupying many weeks. She then furnishes the bottom of the cell with pollen mixed up with honey, lays an egg in the middle of this paste, and closes the cell by a ceiling of saw-dust agglutinated with saliva. On this ceiling she establishes a new cell, and so on, right up to the orifice, which she closes in the same manner. Réaumur is astonished, with reason, at the admirable instinct which makes this provident mother determine the exact quantity of nourishment which will be necessary for its larva. When this has absorbed all its provisions, it alone quite fills up its cell, and changes into a pupa. It is worthy of remark, that the head of the young is always turned downwards, in such a way that it is by the bottom of its cell that it comes out. The bottom of the first is very near the surface of the wood, so that the insect it encloses has only a thin layer of wood to pierce through in order to set itself free. Each one of those which are born next has only to pierce the floor of its hiding-place to find the road before it free. The _Xylocopæ_ pass the winter in the pupa state, and the perfect insects, with wings of a beautiful metallic violet, appear in the spring, but are not found in this country. [Illustration: Fig. 341.--Interior of the Nest of the Mason Bee.] Other solitary bees have their hind legs unsuited for the gathering of pollen, but have the rings of the abdomen furnished with hairs for that purpose. Such are the Mason Bees of Réaumur, belonging to the genera _Osmia_ and _Chalicodoma_,[98] which build their nests against walls with tempered earth, which become very hard.