278 HOUSE, GARDEN, AND FIELD 



in the ground. The leaf-fragments are not cut at hazard ; 

 each has a shape suited to the place which it is destined 

 to occupy. The outer tube is more roughly shaped than 

 the cells, which are beautifully exact. Every cell contains 

 from nine to twelve separate pieces, sometimes many 

 more, and though they are secured neither by stitches nor 

 glue, they keep their shape perfectly. The fitting of the 

 circular lids, each made up of three or four bits of leaf, 

 into the mouth of the cell is an excellent piece of work. 

 The bees often employ the disused burrows of earthworms, 

 but are careful to stuff up the lower part of the tube with 

 fragments of crumpled leaves, lest an enemy should enter 

 from below. Some employ the holes excavated in tree- 

 trunks by beetle-larvae or wood-wasps. If the hole is wide, 

 they will arrange their cells in two or three rows instead of a 

 single row as usual. When all the cells are filled, the bee 

 makes up the entrance with crumpled leaf-fragments, and 

 comes back no more. The grub consumes its store of honey, 

 and then enters upon its winter sleep, pupating in autumn 

 or spring, but never emerging until the following summer. 



I can only glance at a number of other contrivances 

 employed by other solitary bees. Various species of 

 Osmia utilise stacked reeds, burrows of other insects, 

 and even snail-shells for their stores of food. Some bees 

 employ the dead branches of blackberries, which are 

 easily hollowed out because they are filled with soft pith ; 

 one species makes a collection of cells out of chewed leaves ; 

 another not only employs empty snail-shells, but conceals 

 them in a dense mass of sticks and straws. Mason-bees 

 build up tubes of small stones, which they fasten together 

 with a secretion which sets hard like cement. Halictus 

 makes a rude comb of cylindrical cells out of clay, and 

 lines them with hardened saliva. The carder bee (Anthi- 

 dium) strips off the woolly or cottony covering of certain 

 herbs, and lines her burrows with it. Other carder-bees 

 imitate that species of Osmia which chooses snail-shells 

 for its nest, but subdivide the cavity by partitions of 



