278 THE ANTHOPHILA. 



months hovering over flowers, and of which the female 

 is remarkable for having a pair of curious horns 

 standing out from the lower part of the face, appears 

 to vary its habits according to the locality in which 

 it lives, in some places burrowing into sunny banks 

 and cliffs, whilst in others it selects the dead trunks 

 of trees for the construction of its nests, and not un- 

 frequently also burrows into the soft mortar of old 

 walls. A very local species, the O. leucomelana, forms 

 her nests in the dead stems of the bramble, each 

 consisting of five orix cells, placed one above the 

 other, and separated by a partition composed of mas- 

 ticated vegetable matter ; and it is remarkable that 

 the mother Bee does not clear out the whole of the 

 pith so as to make a uniform tubular burrow, but 

 leaves little ring-like projections here and there, 

 marking the divisions of the cells, and thus saves 

 herself a good deal of unnecessary trouble in subse- 

 quently closing them up. Other species, such as the 

 O. aurulenta and bicolor, both of which are common 

 in the South of England, usually burrow into sand- 

 banks, but frequently exhibit curious deviations from 

 this habit. Thus, like the Chelostoma, already re- 

 ferred to, they often construct their nests in thatch, 

 and sometimes also in a still more remarkable situ- 

 ation, namely in the shells of snails. In the shells of 

 the smaller snails (such as Helix hortensis and nemo- 

 ralis] the Bee deposits a mass of pollen and honey, 

 upon which she lays an egg, and then shuts the whole 

 off by a transverse partition formed of masticated 

 vegetable matter. Another egg is then deposited with 

 a supply of food in the same shell, and this is closed 

 in by a partition, and the same operation is repeated 

 until the shell has received as many cells (from five 



