outer skin.

[Illustration: FIG. 10.]

The maggots reach their full growth in about two weeks, when they are
about one-third of an inch long, white and glossy, tapering from the
posterior end to the head, which is armed with a pair of black,
hook-like jaws. The opposite end is cut off obliquely and has eight
tooth-like projections around the edge, and a pair of small brown
tubercles near the middle. Fig. 11 shows the eggs, larva, and pupa,
natural size and enlarged.

[Illustration: FIG. 11.]

They usually leave the onions and transform to pupæ within the ground.
The form of the pupa does not differ very much from the maggot, but
the skin has hardened and changed to a chestnut brown color, and they
remain in this stage about two weeks in the summer, when the perfect
flies emerge. There are successive broods during the season, and the
winter is passed in the pupa stage.

The following remedies have been suggested:

Scattering dry, unleached wood ashes over the plants as soon as they
are up, while they are wet with dew, and continuing this as often as
once a week through the month of June, is said to prevent the deposit
of eggs on the plants.

Planting the onions in a new place as remote as possible from where
they were grown the previous year has been found useful, as the flies