2 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. 
this insect had become quite common, and many of the buds were 
covered with the females and young. Examination of surrounding 
localities disclosed the same conditions of infestation. The aphides 
increased rapidly until the cold weather in December checked, 
although it did not entirely stop, their reproduction and growth. In 
January, warmer weather again prevailing, the rosebushes began to 
grow rapidly, and the rose aphis became very abundant on the tender 
stems and buds. It continued abundant and developed rapidly dur- 
ing the months of February and March, although syrphus-fly larvae 
devoured thousands. Early in April, however, there occurred sev- 
eral very warm days when the temperature rose to 100° or 101° F., 
and immediately the numbers of aphides were greatly reduced. 
Afterwards the aphis occurred scatteringly on the roses and caused 
very little damage. This was due in part to extreme heat and the 
work -of parasitic and predaceous enemies, and to the fact that in 
June the roses became more or less dormant and ceased active 
growth for some weeks. By the middle of August the rosebushes 
had resumed active growth, and this insect again began to increase 
rapidly and to cause damage, continuing to multiply and injure the 
roses until October 1, 1910, when observations ceased. 
At Waslungton, D. C, during October and November, 1912, this 
aphis was very abundant and injurious to roses grown in the yards 
and gardens of the city. But by November 29 only a few aphides 
remained on the plants, although these persisted as late as Decem- 
ber 16. 
DESCRIPTION. 1 
The rose aphis occurs in two forms, one in which the body is of a 
pinkish color and the other in which the pink is replaced by bright 
green. Both forms may be present on the same bush or twig, and in 
some cases all on one bush may be green and all on another near it 
pink. It would appear from the writer's observations that the green 
aphides are much more abundant during the cooler months than the 
pink f orms. 
The winged female (tig. 1, a) has a pear-shaped body which in one 
form is pinkish and in the other bright green. The thorax is largely 
black, apparently deeper black in the green form, and there is a row 
of black spots on either side of the abdomen. These colors may vary 
slightly in shade. The antennas, cornicles, ends of femora, and the 
tarsi are black, while the other parts of the legs are whitish. In both 
pink and green forms, however, the head may be entirely black, and 
the black antennae and cornicles may be hyaline at the tips. The 
i Another aphis commonly found on the rose is known as the small green rose aphis (M'jzus rosarum 
Walk.), hut this can be distinguished by its smaller size and by the fact that it has only a green form. 
This species is shown in figure 2, in both -winged state (a) and wingless state (b) with many details of struc- 
ture. This aphis will yield to the same treatments as the common rose aphis. 
