8 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. 
Table I. — Reproduction and development of the rose aphis, Macrosiphum rosae, in 
southern California, 1909-10 — Continued. 
Date of birth of female unknown; 
Winged female, red form; gave 
birth 
gave birth to first young Jan. 3, 
to first young Mar. 3, 1910— Con- 
1910: Number of 
tinued. 
Number of 
young. 
young. 
Jan. 3 2 
7 
5 
4 2 
8 
3 
6 9 
9 
o 
8 i 1 ) 
Total 
32 
Total 13 
Average per day . . 
5* 
Average per day 3 
Mar. 7 
5 

Winged female, red form; gave birth 
to first young Mar. 3, 1910: 
8 
5 
9 
7 
Mar. 3 5 
10 
C 1 ) 
4 5 
5 9 
Total 
17 
6 5 
Average per dav - - 
5# 
Two females were observed that produced 30 and 40 young, respec- 
tively, after which they died under normal conditions. They pro- 
duced young on an average of 2 and 2 J per day for 15 and 20 days, 
respectively, during the month of December. Other females observed 
during the same period, but lost possibly before reproduction was 
completed, gave birth to from 15 to 45 young at an average of 3 \ per 
day. Two females observed in the month of March, however, pro- 
duced young at the rate of 5 J and 5§ a day, showing quite plainly 
how the reproduction was accelerated during the prevalence of 
warmer temperatures. Two females in October reproduced young 
at the rate of 5J a day for 6 days, or until lost. 
From these observations it may be said that this insect is able to 
reproduce for at least 20 days during the winter in southern California 
and to give birth to as many as 45 young, while in the warmer seasons 
the number of young is probably greater and the period of reproduc- 
tion is considerably shorter. The reproduction experiments were too 
few in number to justify making any statements more generalized 
than these. 
LIFE HISTORY AND REPRODUCTION IN THE GREENHOUSE. 
During the fall of 1912 the rose aphis was under the direct observa- 
tion of the writer in the insectary greenhouse at Washington, D. C, 
and the life cycle was observed for a few individuals. 
A wingless female born October 10 matured and gave birth to young 
on October 19, or in 9 days. During the next 7 days she gave birth 
to 45 young, or an average of 6f per day. 
Aphis lost. 
