8 BULLETIN 774, U. S. DEPARTMENT OF AGRICULTURE. 
In 1916 infested prune leaves began to curl at the beginning of 
April, such leaves having one or more colonies of adult stem mothers 
and first-instar young. As April progressed the leaf-curl became 
more and more pronounced and the colenies increased rapidly. 
About the middle of the month the most heavily infested leaves 
began to have a yellowish appearance in the form of blotched areas 
at the points where the aphids were most abundantly settled. On 
April 21 a few leaves were found to have their under surfaces quite 
covered with feeding aphids, and at the end of the month such leaves 
were SUL while twigs and limbs were covered with a sticky 
“honeydew,” and here and there young fruits, were coated with this 
substance. During May and June this condition was greatly aggra- 
vated in the orchards examined. 
The spring winged form first appeared April 21, and throughout 
May and June increased in numbers, and after the middle of May 
there was a corresponding decrease in the numbers of wingless adults 
produced. By July 1 the mature wingless individuals had dimin- 
ished greatly in quantity and thereafter their numbers dwindled so 
that by the middle of August none were to be found. In no instance 
in 1916 was an infestation prolonged beyond this date, but in 1914 
in the same locality a small but vigorous infestation occurred through- 
out September, later becoming annihilated by natural enemies. 
In the rearing cages it was found that the transfer of newly born 
young was very frequently attended by the loss of the insect, and 
in most cases the adult was transferred when it was desired to make 
observations on a new plant. Several transfers of larve and adult 
wingless individuals from plum to apricot failed, while others re- 
sulted successfully. Infested apricot leaves did not curl as badly 
as those of prune and plum. 
THE SPRING MIGRANT. 
DESCRIPTION. 
In the first three instars the nymphs of the migrants do not differ from those 
of the wingless spring form, except that the third-instar individuals are some- 
what narrower. 
Pupa.—tLight green; eyes dark red; tarsi and apex of beak dark gray. On 
the body ground color is superimposed a narrow dorsomedian stripe of darker 
green. Thorax broadened to twice the width of the prothorax. Wing pads 
yellowish white. Body with pruinose covering as in wingless nymph. 
Adult.—Light green; eyes red; antennez light gray, basal portion of third 
joint hyaline yellow; head, thoracic lobes, and sternum dark grayish black; 
scutellum yellowish brown; prothorax, sides of thorax, and wing insertions 
greenish yellow; wings hyaline, stigma and veins gray; legs pale greenish yellow, 
apices of tibiz and the tarsi dusky gray; abdomen and style pale green or 
greenish yellow; cornicles pale at base, dusky at apex. Beak pale, extreme tip 
dusky. 
Form elongate, the abdomen with parallel sides. 
The dorsum and sides are covered with white pruinose “ meal,” on the ab- 
domen the “meal” occurring in transverse bars. 
