10 BULLETIN 90, U. S. DEPARTMENT OF AGRICULTURE. 
HEAT. 
During the early part of April, 1910, when the aphis was very abun- 
dant on the roses throughout the entire city of Los Angeles, three or 
four very hot days occurred during which the temperature rose as high 
as 100° F., and within a day or two thereafter the numbers of this 
aphis had become very much dirnimshed. After this it did not seem 
to occur in large numbers again until about the middle of August. 
BIRDS. 
On March 19, 1910, the writer, with field glasses, watched a white- 
crowned sparrow (ZonotricJiia leucophrys leucophrys) on a rosebush 
10 feet away, eating the rose aphides as fast as it could pick them 
from the bush. This was continued for fully 10 minutes, during which 
time many hundreds must have been eaten, as the plant was almost 
cleaned up by this bird. 
On March 30, 1910, a California house finch (Carpodacus mexicanu 
frontalis) was observed by the writer eating this aphis from a rose- 
bush for fully 15 minutes. 
PARASITIC INSECT ENEMIES. 
There are many different species of parasitic insect enemies that 
attack aphides, and some of these will attack the rose aphis. On 
June 13, 1910, many specimens of Macrosiphum rosse were found 
which showed signs of parasitism by an undetermined insect. These 
aphides were rounded and fastened to the underside of the rose leaves. 
The parasite when full grown had killed the host and, cutting its way 
out beneath the body, spun a tiny cocoon between it and the leaf. 
Unfortunately all of the parasites failed to emerge. While the para- 
site was not rare, at least during the past year, it did not seem to 
check the rose aphis to any extent. 
Ephedrus incompletus Prov., a braconid, was reared by the writer 
from this aphis at Washington, D. C, in 1912. 
PREDACEOUS INSECTS. 
Among the predaceous enemies the larvae of syrphus flies and lady- 
birds were observed feeding on the rose aphis, and without a doubt 
the most important check to this insect in 1910 was due to the larvae of 
syrphus flies. TThile these did not seem able to clear a plant alto- 
gether, still it was mam' times observed that strong thriving colonies 
of 50 to 60 aphides or more would be reduced by these insects hi one 
or two days to a mere scattering here and there. During the }~ear 
1910 Ave different species of Syrphidae were reared from larvae feeding 
on jfacrosipJium rosse. These were Syrphus ribesii L. (fig. 3), SyrpTius 
opinator O. S., AUograpta fracta O. S., Eupeodcs volucris O. S. (fig. 4). 
and Lasiophthicus pyrasti L. 
