704. Rosert MATHESON 
migrate until a satisfactory locaton is found, usually on the underside 
of a leaf or on the succulent new growth. Here they may congregate 
in considerable numbers, insert their beaks into the leaves, and, as they 
feed, bring forth their young. Once located they seldom move. except. 
when disturbed or when crowding becomes excessive, when they may 
be observed searching out new feeding places. 
Winged forms.— The activities of the winged forms are much more 
varied and are of considerable significance for the species. The insects 
appear very excitable, and when disturbed they move about actively 
or readily take to flight. They do not settle permanently in any one 
place, but feed for shorter or longer periods on either the leaves or the 
succulent young growths. They deposit their young from time to time, 
and the species is distributed very rapidly during the early days of June. 
Frequently, if the stem mothers have been fairly abundant, considerable 
flights of the winged forms may be observed in the early days of June; 
and it is not at all uncommon at that time to find practically all the lower 
and outer leaves of trees that had previously been free of lice with two or 
three winged lice on each leaf. | 
Reproductive capacity ; 
Wingless forms.— In the writer’s rearing work, the reproductive capac- 
ity of the wingless forms was not so great as that. of the stem mothers. 
This may be seen by consulting the chart, the reproductive capacity of 
five individuals varying from 34 to 58. The period of reproduction is 
considerably shorter than that of the stem mothers, and the daily rate 
of production is much higher. 
Winged forms.— In the winged forms the number of young produced 
averages less than in the wingless forms, the productive period is 
shorter, and the average daily rate is about the same. In the case of 
the winged forms it was rather difficult to obtain accurate results, owing 
to the wandering habits of the insects and the fact that the cages, tho 
of considerable size, did not seem to allow normal development. From 
such considerations the writer is inclined to believe that the reproductive 
capacity shown in the experiments is too low. 
Both forms.— From all the cage records, the total length of life of the 
apterous forms of this generation appears to be about the same as that of 
the stem mothers, whereas the winged forms have a considerably shorter 
life. . Field observations have confirmed the cage experiments in this regard. . 
