960 I. M. HawiEry 
Is it possible that manure has an attraction for the maggots developing 
from eggs deposited in the soil, which leads them to use It as a secondary 
host ? 
In cages, eggs of the first brood have been found singly as a rule, tho they 
have been found occasionally in groups of from two to five, in some cases 
side by side and in other cases piled on one another irregularly. When 
first-brood flies taken in the field were placed in cages, eggs were deposited 
on decaying mustard stems, on stems and roots of grass, on old bean pods 
and vines, and on cabbage stumps. Some eggs were found a so on the sur- 
face of the ground, and some in the top inch of dirt. few were attached to 
the side of the flower-pot, both above and below the soil line. Eggs of 
the second brood were deposited by flies in captivity on top of the soil and 
in the dirt itself. 
Number of eggs 
The writer has not been able to bring about oviposition by flies reared 
in captivity, and accordingly he could not determine the exact number of 
eggs deposited by a single female. The following may be mentioned as 
typical examples of many dissected specimens. On May 27, 1918, 87 
eggs, of which 25 were almost fully developed, were found in a dissected 
fly. On May 15, 1919, two flies were found with nearly mature eggs, one 
containing 30 and the other 48. In 1920 two:flies were found containing 
83 and 64 eggs, respectively, on May 7; and on May 19, five flies contained, 
respectively, 56, 25, 37, 85, and 72 eggs. It is believed that all the eggs 
in an insect mature at about the same time and that oviposition is completed 
within a few days. From these data it seems possible that a female may 
deposit 80 or more eggs, but the number may often be much smaller. 
/ 
Time of oviposition 
Since it is from the eggs of the first brood of flies that the maggots so_ 
injurious to growing crops are produced, special study has been given to | 
this generation. Very little is known of conditions in 1917, as life-history | 
studies did not begin until June 22. In 1918 adults were found containing | 
well-developed eggs on May 9, and, tho some eggs were no doubt deposited | 
by May 15, most of the eggs of the first brood were deposited between | 
May 23 and June 1. Eggs of the second brood were deposited during the | 
first half of July. 
In 1919 eggs of the first generation were mostly deposited from May 20 | 
to June 15, with the maximum deposition occurring about June 4. Second- | 
brood flies were ready to oviposit between June 25 and July 4. Since a | 
few flies were captured on September 13 and 15 whose abdomens contained | 
immature eggs, 1t seems possible that a few eggs may have been deposited | 
as late as October. However, these flies may hibernate, which would | 
explain why a few flies with well-developed eggs are found in early May, | 
several weeks ahead of most of the first brood. 
