THE HOP PLANT-LOUSE. 
(Phorodon humutli.) 
LIFE HISTORY. 
Wherever it occurs, whether in England or on the continent of Europe, 
in New York, Wisconsin, or on the Pacific coast, the Hop Plant-louse has 
substantially the same life round. 
The eggs are laid in the fall on dif- 
ferent varieties and species of the 
Plum, both wild and cultivated. 
They are small, glossy, black, ovoid, 
and are attached to the terminal 
twigs especially in the more or less 
protected crevices around the buds 
(Fig. 1). From this egg there hatches 
Fic. 1.—Winter-eggs of the Hop Plant-louse, in the spring, about the time when 
ae ea ee the sexual female which the plum buds begin to burst, a 
* stout female plant-louse, known as 
the stem-mother, which differs from the sum- 
mer individuals by having shorter legs and 
shorter honey-tubes (Fig. 2). She gives 
birth, without the intervention of the male, to 
living young, and this method of propagation 
continues till the last generation of the sea- 
son. The second generation grows to full 
size and gives birth to a third, which becomes 
winged (Fig. 3), and develops after the hops 
have made considerable growth in the yards. 
The winged lice then fly from the plums to 
the hops, deserting the plum trees entirely 
and settling upon the leaves of the hops, 
wheromtheyibesin, eiving, birth to another: 7S 7. The Hop Flantlouse, 
i % é re stem-mother, with enlarged an- 
gene. ation of wingless individuals. tenna above—enlarged. 
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