980 
Journal of Agricultural Research 
Vol. V, No. 91 
REPRODUCTION 
Reproduction was perfectly normal. Both wingless and winged 
forms were produced, though the percentage of wingless forms was a little 
greater than by the wingless mothers. Three adults produced 81 young, 
an average of 27. This is much below the average for the other forms, 
but only 3 insects were used, and there is nothing to indicate that, nor¬ 
mally, this form would not produce at least as many young as the winged 
mothers. The average daily reproduction was 2.13 for these three indi¬ 
viduals, this being somewhat less than that of either of the other forms. 
Here, again, however, the small number of mothers detracts from the 
comparative value of the figures. 
LONGEVITY 
The average length of life for these three insects was 24.3 days, one 
living 27 days. 
COMPARISON OF THE THREE FORMS 
NYMPHAL STAGES 
All three forms agree in having four immature stages, the first three 
existing for equal periods, while the last stage is about two days longer 
in the winged individuals and ftitermediates than in the wingless ones. 
REPRODUCTION 
Table II gives a comparison of the reproductive activities of the three 
forms. 
Table II. —Comparison of the reproductive activities of the three summer forms of 
Aphis pomi 
