Feb. 21, 1916 
Green Apple Aphis 
989 
longevity 
The longest record we have for total life of females is 47 days. At 
the end of this period the experiment containing two females was set 
aside and was not examined again for a month. At this time all were 
dead. The average life for the sexual females is about 25 days. The 
period varies with climatic conditions, insects bom late in the season 
not living as long as those bom in September. The total life period of 
the male appears to be considerably shorter than that of the female. 
The longest period observed was 31 days. In this case the male was 
never transferred from the plant on which it was bom, and several 
females were present. When a male was transferred to a new tree 
bearing only one or two females, it usually disappeared within a week. 
In some cases it died, but often it could not be located at all. Toward the 
end of the season females were still quite abundant, but no males could 
be found. 
The last oviparous females were observed, under natural conditions, 
on November 27. They were on a tree which still bore five or six green 
leaves. The next day these leaves fell and no more insects could be 
found. In the cages living oviparous females were present on January 
5, at which time all experiments were closed. 
HARDINESS 
This species, particularly the oviparous females, can withstand very 
severe temperatures. On January 5, 1915, observations were made 
on some experiments in the insectary. These experiments contained 
both viviparous and oviparous females. At this date all the viviparous 
and most of the oviparous females were dead. However, on one plant 
one living insect was found, while a second plant bore six insects which 
were alive. These latter six were very quiet, showing only the slightest 
movement when disturbed. The other one, however, was quite active 
and moved about on the plant. At the time the observations were 
made (2 p. m.) the temperature was 43 0 F., and these insects had been 
subjected to such low temperatures several times, the minimum being 
— 6 °. 
MATING 
The oviparous females may mate within two days, and possibly in 
less time than that, after reaching maturity. On the other hand, a 
female may mate for the first time at least eight days after having 
become adult. The principal factor in determining this point is the 
facility with which the male finds the female. 
Males have lived for considerable periods of time, as much as 10 days, 
and have spent much of the time on the same leaf with the female, and 
yet mating apparently did not take place. When males have been placed 
