338 
Journal of Agricultural Research 
Vol. VII, No. y 
Color characters: Similar to those of the spring migrant. Abdomen usually with 
one large central black patch, three or four marginal patches, and a transverse band 
caudad of the cornicles, this band extending cephalad at its edges to touch the base of 
the cornicles. In some specimens the whole of the abdomen appears a uniform black 
and the legs also do not show the yellow regions usually met with.. 
Location: Upon the leaves of the plantain, usually upon the underside, and upon the 
underside of the leaves of the apple, depositing young oviparous females. 
LENGTH OF NYMPHAL PERIOD 
The length of the nymphal period varied from 13 or 14 days in early 
September to as much as 24 days for aphids bom in October. The 
average period was 16 to 18 days. No figures for the various instars can 
be given since they varied greatly with the temperature, so that, while in 
one case the first instar might be the longest, in others the third or fourth 
would be. 
REPRODUCTION 
Sixteen fall migrants produced 114 yoting, an average of 7.1 young per 
mother. The greatest number produced by one mother was 13 (or 
more), two insects together producing 25; the smallest number was 3. 
The average length of the reproductive period of 25 insects was 5 days, 
varying from 1 to 10 days. In every case all but one or two of the young 
were produced within a period of 1 to at most 2 days. Later at periods 
varying from 3 to 8 days one or two more young might be produced. 
LONGEVITY 
The adults of this form usually lived for a considerable period after 
reproduction ceased, this period varying from 2 to (in one case) over 
40 days. 1 The average length of this post-reproductive period for 15 
insects was 23.6 days. 
The longest total life recorded was 62 days, while the average was 
about 45 days. 
The conditions with regard to the rate of opposition found to exist 
among both spring and fall migrants are very interesting, since they 
are the exact opposite of the theoretical conditions for insects. The 
general statement is commonly made that those females which produce 
all their eggs (01 progeny) in a short period die very soon afterwards, 
while the females which live for a long time are those which produce 
only a few eggs (or young) daily. In this case, however, the adults 
produce their young in a short period and then proceed to live for many 
days. The theory is based, in part at least, on the proposition that the 
insects which produce all their offspring or progeny within a short 
period become exhausted, and, of course, with these migrants only a 
small number of young are produced. Still, in so far as the general 
theory endeavors to explain the causes of a long adult life, it fails for 
these forms. 
1 Experiment closed before insect died. 
