NOVEMBER 1ST.

THE BLUE BOTTLE, OR FLESH FLY.-(Musca vomitoria.)

THICKLY scattered over the glossy leaves and flowers of the ivy, and sporting in the sunbeams, may now be seen numbers of this well-known Fly. The fore part is black and hairy; the abdomen of a shining steel blue. During night and early morning the insects seek shelter under the leaves and matted roots of the ivy, and in sunny days creep out to bask in the sunbeams and sip the honey from the flowers. Possibly a few only of the numbers we now see may be able to endure the rigour of the coming season; but those few will suffice, under favourable circumstances, to stock the whole country. It has been ascertained that a single female Fly will deposit some 20,000 eggs. These are most curiously rolled up, filling nearly the whole of the abdomen of the insect; as soon as a fitting substance is found, the reel is gradually unwound, and the eggs deposited in quick succession. In sultry weather the grubs are produced in a few hours, and then yellowish white maggots are seen actively engaged. They are the most astounding gluttons. The pointed part of the grub is the head, the broad and flat end, the tail; but as the latter is marked with two black specks like eyes, it is often considered the head. The maggot having managed to increase its weight to an enormous extent (Redi ascertained by experiment that it became from 140 to 200 times heavier in 24 hours)—the chrysalis stage is assumed, the skin dries round the grub, and it lies dormant for some days; at last the Fly emerges, and commences industriously its vocation for man's advantage. Wherever decaying animal substance is found, there is the Flesh Fly actively engaged removing that which would otherwise create disease, and probably cause death -as putrefaction goes on, new life consumes it, and thus the