Under the magnifying glass they look like tiny cicadas.
See, here is a picture of one enlarged.
Their natural size is no larger than a plant louse.
Have you not often seen them clustered close together on the young twigs of pear trees—tiny, light-colored things that jumped in all directions when you touched the twig?
The name of the plant louse that infests pear trees is the pear-tree psylla. It is very destructive to pear trees, sucking out the juices of the young shoots.
The pear trees can be saved by spraying them with kerosene emulsion as soon as the young leaves have opened in the spring.
The Aphids
Now, let us go in search of the aphids, or aphides, as they are also called. We shall not have to search far.