32S DIPTERA. 
creatures, and which endowed those 
creatures with the faculties requisite to 
perform a useful part in the beneficent 
economy of the universe ! 
Lucy. Dear mamma, can those ani- 
mals, which destroy and spoil our meat, 
be of any use ? 
Mother, There is no race of animated 
nature which is not in some way conducive 
to the general benefit. These flesh maggots 
are of essential service, by speedily de- 
stroying the putrid carcases of dead ani- 
mals, which would otherwise be an in* 
tolerable nuisance. These worms con- 
tinue their depredations for seven or 
eight days, and then bury themselves in 
some loose earth. 
Lucy, Where, I suppose, they change 
to chrysalids ? 
Mother, They do so ; in the progress 
of their change the body contracts in 
length, and enlarges in thickness, till it 
acquires the form, and indeed the appear- 
ance, of an egg\; and the skin, which is 
at first white and soft, gradually alters to 
