978 
Journal of Agricultural Research 
Vol. V, No. 21 
LONGEVITY 
The longest total life recorded for an individual of this form was 42 
days. 
FLIGHT 
A large number of migrants of the second generation were reared on 
some small apple trees in the laboratory. These insects, on becoming 
adult, were very active, and several hundred were taken on the windows 
of the room in which they were confined. They were to a marked degree 
negatively geotropic. This was well illustrated by the fact that as many 
as 25 could be kept safely in a small open vial by simply holding it upside 
down. Almost without exception migrants transferred to new plants 
settled readily and made no attempt to fly farther. They were very 
likely to fly from the brush, however, during the process of transfer. 
In the case of the later winged forms no such tendency toward flight 
was observed. In no case were winged aphides observed which had left 
the plants and clustered on the sides and tops of the cages, unless the 
plants were so nearly dead that the wingless forms also left them. More¬ 
over, no particular caution was necessary in transferring them from one 
plant to another, since they showed no inclination toward flight. This 
would seem to indicate that the winged forms of the second generation 
alone correspond to the spring migrants of species with a definite alter¬ 
nation of hosts. 
intermediate; form (pl. lxvii, fig. 6) 
description 
Morphological characters: Antennae (PI. LXXIV, fig. 6) as follows: I, 0.064 mm.; 
II, 0.064 mm.; Ill, 0.28 to 0.34 mm.; IV, 0.16 to 0.24 mm.; V, 0.144 to 0.208 mm.; VI, 
base 0.096 to 0.12 mm., unguis 0.176 to 0.328 mm. Antennal segments armed as in 
wingless individuals, with the exception of segment III, which is armed with unequal 
sized sensoria, varying from 4 to 6 in number. Vertex rounded; eyes with ocular 
tubercles present; ocelli absent, even from specimens with nearly half-size wing rudi¬ 
ments. Thorax and abdomen with tubercles as in the wingless form. Thorax not 
showing the distinct “corseletta” of the winged form, but indicating a series in these 
forms from the winged to the wingless condition. Wings of winged form represented 
here by reduced wings of about half the normal size, through gradations in different 
individuals until mere folds of the skin are seen. Cornicles subcylindric, tapering 
distad, imbricated, and slightly flanged; length, 0.272 to 0.496 mm. Anal plate 
rounded, setose, and armed with long hairs. Cauda elongate, slightly constricted in 
the middle, rounded at the tip, densely setose, and armed with five or six long curved 
hairs on each side. Leg slender, hairy; hind tibia 0.608 to 0.896 mm. long. Length of 
insect from vertex to tip of cauda, about 2.5 mm., but with much variation. 
In general outline the intermediate conforms much more closely to the wingless 
insect than to the pupa, being plump and of regular outline without having the thorax 
sharply delineated. 
Color characters: In color characters this form resembles the wingless female very 
closely. In most specimens the rudiments of the wings are of a light green color, 
