51 
sparsely covered with long stiff black hairs. When in action the 
body is carried usually in a somewhat curved position, but when 
extended measures nearly a quarter of an inch. The maggot (f) is 
white, and so nearly transparent that the contents of the abdomen can 
be seen through the posterior portion. 
In many cases infestation can be traced directly to the insects hav- 
ing bred in lambs-quarters and similar weeds, which if not destroyed 
by ordinary methods of cultivation mature and die during October. 
The flies, by close observation, may be seen in flight just above the 
ground or hovering about their different food plants. The eggs 
are placed on the lower surface of the leaves and arranged in masses 
of from two to five. When the young hatch they bury themselves 
Fig. bO.—Pegomya vicina: a, fly; b, head of male flj^; c, head of female; 'd, surface of egg, highly mag- 
nified; €, egg; /, maggot; g, head of same; h, cephalic hooks of maggot; i, prothoracic spiracles; 
j, anal segment; k, anal spiracles; I, puparium — all enlarged (after Howard, Division of Entomology). 
within the leaf tissue, constructing a thread-like mine which they after- 
wards extend in a curve or semicircle. 
Transformation to pupas takes place in most cases in loose soil, 
which the maggots enter only to a short distance or under fallen leaves. 
Occasionally maggots transform within a leaf if the latter happens to 
rest on the ground. 
Injury appears to be most frequent in late fall, but may be due to 
earlier generations in midsummer. Dr. Howard states that eggs 
hatch in from three to four days, and the larval stage is passed in seven 
or eight days, the puparium or resting stage requiring from ten to 
twenty days. These periods will vary according to the state of the 
atmosphere. An instance of damage to spinach in Pennsylvania was 
reported in May, 1903. 
