724 RoBERT MATHESON 
Another interesting point in support of the above statement is the 
fact that Plantago lanceolata is primarily a plant of the meadows, thus 
providing ideal conditions for the development of Aphzs sorbi in and 
about orchards. Plantago major, on the other hand, is a roadside weed, 
thick-leaved, sturdy, and well able to thrive under unfavorable con- 
ditions. Such a plant does not seem to be a favorabie host for such 
a delicate insect as the summer forms of the rosy aphis. 
DISTRIBUTION 
Altho the species Aphis sorbi was first recorded in Illinois in 1854, 
it is still difficult, owing to the confused condition of the literature, to 
state its exact distribution. It has been definitely recorded from Delaware, 
New Jersey, New York, Connecticut, Maine, Ohio, Oregon, and Colorado, 
and from various sections of Canada particularly in the apple-growing 
sections of Ontario, Nova Scotia, Quebec, and British Columbia. In all 
probability this plant louse is widely distributed in the apple-growing 
sections of the United States and Canada, but it has been so confused 
with Aphis pomi and Aphis avenae that it is hopeless to try to untangle 
the various brief references. 
NATURAL HISTORY 
Aphis sorbi, like Aphis pomt and Aphis avenae, deposits its eggs on 
apple trees, and hibernation takes place, in the north at least, only in 
the egg stage. Hatching occurs early in the spring, about a week to 
ten days later than in the case of Aphis avenae and at about the same 
time as in Aphis pomi. For 1914 this was on April 26 and for 1915 on— 
April 27. Close observations about Ithaca during the past three years 
clearly prove that comparatively few eggs of this species were deposited 
in this locality. As a result a very small number of the stem mothers 
were observed in the spring, yet, despite this fact, there was a severe 
infestation with serious loss of fruit in 1914, and there would also have 
been a similar condition in 1915 had there not been a timely application 
of adequate control measures. 
Owing to the comparative rarity of the return migrants during the 
autumns of 1914 and 1915, very little work has been done on the egg 
stage of this species. The shy and wandering habits of the insects, com- 
bined with their scarcity, made futile any hopes for an adequate supply 
