LETTEBS ON ENTOMOLOGY. 129 
has collected enough, she puts it in and closes 
the cell. When the maggot has consumed its 
food, it changes to a nymph, and afterwards to 
a bee. We may call these the carpenters, and 
those of which I shall next speak, the masons; 
they make very good mortar for building their 
nests, which are collections of cells under one 
cover. They prefer attaching them to walls 
exposed to the sun, but though they are often 
as large as half an egg cut longways, they are 
generally passed over as a lump of mortar or 
mud ; but when examined, eight or ten cavities, 
more or less, are discovered, some filled with 
very small maggots in a quantity of paste, others 
with large ones and little paste, and others with 
nymphs and bees. These cells are in the form 
of a thimble with an egg at the end, and are 
quite filled up with paste, and stopped at the 
large end. When this is done, the bee (for it 
is all performed by one) fills up the spaces be- 
tween the cells with rougher mortar. This sub- 
stance is like ours, chiefly composed of sand, 
but mixed with a little earth ; however, she does 
not make use of lime as we do, but substitutes a 
glutinous liquor from her mouth. After having 
made a little lump, she carries and fixes it with 
her teeth. What indefatigable industry must be 
g5 
