135 
oval puparia (Fig. 25) in the bulbs or in the earth not far from 
the onions in which they have been feeding. These puparia trans- 
Fig. 25. Onion-maggot, Phorbia ccparuw, pupariuni. Length 
about one-fourth inch. 
form to adult flies in about two weeks, and the flies, in turn, de- 
posit eggs for a second generation. 
Fig. 
2b. Onion-maggot, Phorbia ccparum, larva, side view. 
Length of body about five-sixteenths of an inch. 
Fig. 2y. Onion-maggot, Phorbia ccparum, tip of larva, top and 
side views. Greatly magnified. 
Natural Enemies. — The onion-maggot has a few parasitic ene- 
mies, but they are seldom numerous enough to hold it in check, 
and have little economic value in Illinois. Chickens and other 
domestic fowds are fond of this insect, but on a large onion farm, 
it would be too difficult and expensive to keep enough of them to 
be of much assistance. 
Methods of Control. — As this insect often lives over the winter 
as a maggot or as a puparium in the onion bulb, it is of great im- 
portance that the fields should be thoroly cleaned up in fall, no 
onions being allowed to remain there over winter. 
As a rule, this pest is more abundant and destructive on com- 
parativelv sheltered areas than in open fields over which the winds 
