194 PLANT LICE. 
Aphis mali. In the same bench, about twenty feet away, wheat 
was sown, while some corn was planted in the intervening space. 
A pot containing a strawberry plant infested with another species 
of Aphis, and which were attended by ants, Lasius flavus, had 
previously been placed on this bench. With the hatching of the 
mali a large portion of the ants abandoned their wards on the 
strawberry and gave their attention to the new one on the apple. 
The strawberry was then removed, but they still clung to their 
new found friends. As the population on the apple increased, 
the ants distributed the apterous females to plants of Poa, Setaria, 
and Ambrosia artemisiefolia, but especially to the wheat; carry- 
ing them by the corn to the wheat beyond, which soon became 
overrun with Aphis. Later they began to colonize their wards 
on the corn,—but this seemed to be less desirable than either 
the wheat or the grass. Winged mali left the apple unaided, 
and after taking up their position on the wheat, began their labor 
of reproduction. On this wheat being uprooted the indefatigable 
ants removed them to a few wheat plants still farther away from 
the apple. 
“The species also lives over winter in the wheat fields, at 
least during mild winters, and I have found females reproducing 
every month of the year. Here, in the west, when the young 
wheat comes up in September and October, the winged females 
appear on the plants, and give birth to their young, and these 
crawling downward attach themselves to the stem just below 
the surface of the ground, or even on the roots themselves. Here 
they go on reproducing when the temperature is favorable, the 
adults being apterous, so far as observed by me, until spring, 
when they ascend to the foliage, the adults being after this both 
winged and wingless. On the stems and roots below the surface 
of the ground, they are of a greenish color, tinged with reddish 
brown, especially posteriorly, the full grown individuals often 
being wholly of a dark brown. It is during autumn that they do 
their greatest injury to wheat by sucking the juices from the 
young plants, often, if on poor land and during dry weather, 
checking their growth and causing the foliage to turn yellow.” 
(Webster). 
The eggs of the Apple Plant-louse can be found in the 
cracks and crevices of the bark of the twigs, and at the base of 
