150 Second Report on Economic Zoology. 
Not only are they laid on prunes, but also on the apple, and 
probably on peach and nectarine. They are firmly attached by a 
gummy excretion formed by the parent, and are too thick-shelled 
to be affected by caustic alkali wash. 
Treatment. 
This pest can easily be kept in hand if attacked in its early 
stages. When once the females commence that remarkable and 
rapid production of living young and the leaves begin to curl up 
they are difficult to destroy ; not only do the curled leaves protect 
them, but they are also covered with mealy powder, which helps 
repel the insecticide. 
Washing should begin as soon as the leaves unfold, and must be 
continued every now and then, at intervals of a week. 
Some good will be done by spraying, even when the leaves are 
curled up, but not so much ; to be successful the lice must be killed 
before they enter the breeding stage. 
Quassia and soft soap, or paraffin emulsion, may be used for this 
purpose. 
Another green aphis, the Hyalopterus pruni, Fabr., also infests 
plums, swarming under the leaves and producing white hoary masses, 
but which do not seem to curl up the leaves in the characteristic 
way done by the common plum aphis. 
This apterous viviparous female is flat, pale green with dark green 
mottlings and a dark dorsal stripe, and dusted with white meal. The 
winged viviparous female is bright pale yellowish-green, with red 
eyes and dark green thoracic lobes ; cornicles green, very small ; legs 
pale green ; the wings with a yellow base and stigma. 
The oviparous female lays her eggs near a leaf bud ; the eggs are 
covered with a mealy coat. 
It may frequently be found doing damage, but not nearly to the 
same extent as the former species. 
Gas Treatment of Nursery Stock before Planting. 
Information has been asked regarding the fumigation of nursery 
stock. All nursery stock should certainly be fumigated. 
The bushes or young trees should be placed in a box or canvas 
tent of known capacity and subjected to the fumes of hydrocyanic 
acid gas for one hour. Large numbers can be treated at once at little 
expense. After the stock is stacked under the tent or in the box a 
