Dec. ii, 1916 
Macrosiphum granarium 
477 
males. This is not conclusive proof, but it certainly indicates that tem¬ 
peratures below 50° F. for a daily minimum in some way exert an in¬ 
fluence on the normal production of the sexes. 
OCCURRENCE OR THE SEXES AND THE PROPORTION OP MAIES TO FEMAIES 
The first published record on the sexes is by Sanderson (13), who 
secured them from indoor rearing cages in April. These were the 
progeny of individuals taken in the fields in January. Notes on file in 
the Bureau of Entomology show that the late E. M. Webster made observa¬ 
tions on the sexes as early as 1884 at Oxford, Ind. He records the males 
appearing as early as September and females in October and November. 
Although the egg was observed, no record was made relative to the 
stem mothers. 
These observations in regard to the sexes agree very well with observa¬ 
tions made by the writer. The young males first made their appearance 
during the last week in September or the first week in October. The 
females usually appear a little later. The males are likely to appear any 
time during the winter if kept in breeding cages indoors. In rearing 
cages indoors they appeared sparingly from September to April, inclusive. 
No oviparous females occurred during the winter. Males undoubtedly 
outnumber the females from the very fact of their occurrence both in and 
out of season. During the breeding season (October and November), 
however, the oviparous females usually outnumber the males, as there 
are from a fourth to a half as many pink individuals (mothers of ovipa¬ 
rous females) as there are males. Each of the slightly pink females may 
produce from 6 to 20 oviparous females, and that would bring the num¬ 
bers of the oviparous females far ahead of those of the males. 
MATING 
Mating occurs sometimes during the first two or three days after the 
female becomes adult, and oviposition begins in ^ to 5 or 6 days, 
depending upon the temperature. Females refuse to deposit eggs 
before mating. If the male is not present the bodies of the females 
become almost twice the normal size. In one case 5 females were 
isolated from males for about 10 days or more. Their bodies increased 
greatly in size, but no eggs were deposited. At the end of that period 
males were .placed in the cage. Mating soon took place. In 10 days 
there were 13 eggs in the cage but all were infertile. 
AGE OP OVIPAROUS FEMALES AT OVIPOSITION 
The length of time for maturity of oviparous as for viviparous females 
depends largely upon temperature. Under the same conditions the ovip¬ 
arous females develop in about the same length of time as the vivip¬ 
arous. Targe numbers of both sexes never reach maturity because of 
