Livia pyri is a reddish insect, abundant on pear trees. Other common species are found on the alder, ash, oak, and nettle.
Fig. 111.—Bythoscopus Venosus (Mag.)
Fig. 112.—Livia Juncorum (Mag.)
Family 9, Aphidæ.—The Aphidæ, or "Plant Lice," "Blight," and "Green Fly," as they are variously called, are amongst the most destructive of insects. They are small and feeble creatures, but make up for their individual insignificance by their immense numbers.
They sometimes exist in countless millions, completely smothering the plants upon which they feed.
Migratory habits seem to be strongly developed among the Aphidæ, hence it is we are so suddenly visited by such enormous quantities of the insects during hot weather in the summer time.
In colour the Aphides are generally green, brown, and black, according to the species. Different kinds live on different plants and trees.
