330 
Journal of Agricultural Research 
Vol. VII, No. 7 
days. In the experiments, with one exception to be noted later, the 
adults died within one or two days after depositing their last young. 
The average number of young deposited by 14 females was 121.8 per 
insect. The greatest number deposited by one female was 180 young, 
the smallest 66 young. It should be noted that the female which de¬ 
posited only 66 young was abnormal. The average daily production 
for the 14 insects was 5.7 per female. The greatest daily average for 
one female was 14.3 young, the mother producing 43 young in 3 days. 
One other aphid produced 60 young in 5 days. In a general way the 
aphids of the earlier generations produced more young than did those 
which came later. No exact statement can be made, however, as there 
was much variation in the matter. 
LONGEVITY 
The average total length of life of 13 of the aphids used in obtaining the 
data on reproduction was 31.4 days. 
As has been previously stated, all but one of the insects in question 
died within one or two days after depositing their last young. One insect, 
however, gave birth to only 66 young and then lived for 11 days more 
without reproducing. This aphid was killed on the eleventh day and 
sectioned. When killed, the insect was apparently perfectly normal, 
except for the fact that the abdomen was darker in color than that of the 
other aphids. This dark color was diffused irregularly over the abdomen 
and appeared to be produced by some change within the body of the 
insect, rather than to be simply a case of melanism in the hypodermal 
coloring. The insect was very plump; in fact, much plumper than were 
other aphids which had produced even less young. 
On sectioning it was found that there was an almost complete dis¬ 
integration of the reproductive system, only small isolated portions being 
present. Moreover, there were the remnants of two half-grown embryos 
lying free in the coeloma. The fat body had made an excessive growth, 
almost completely filling the abdomen, and being abundant in the thorax. 
The digestive canal was apparently perfectly normal, as were the other 
organs of the body. 
It is very interesting to note in this connection that three examples of 
a similar nature were found in experiments on the life history of Aphis 
avenae. 
INTERMEDIATE FORM 
* During the spring of 1914 two intermediates (PI. 21, D) of this species 
were reared. These two insects are of particular interest since the other 
intermediates reared have all occurred among the summer forms, the 
winged insects of which migrate, if at all, to other plants of the same 
species as those upon which the wingless insects feed. These two insects, 
however, were reared in the spring upon apple. Had they become 
