Plants as Affected by Animal Parasites. 159 
in which it works its injury, as upon this will depend the 
preventive measures to be used. 
306. Injurious Insects are referable to Two Classes, 
viz., eating insects, i. e., those feeding directly upon the plant 
tissues, aS the potato beetle, 
the apple-tree borers,* the 
plum curculio;, and the 
sucking insects, i. e., those 
feeding only upon the juices of 
the plant, as plant lice, the 
squash-bug,? the oyster-shell 
bark-louse. 2 
Fic. 69. 
Fig. 68. A convenient and serviceable spray pump, using a common pail fora 
reservoir. 
Fig.69. A similar pump with attachment by which kerosene and water may be 
sprayed together (294). Both are made by the Deming Co., Salem, O. 
307. The Eating Insects, may be subdivided into leaf 
eaters, those that devour the foliage; root-eaters, those that 
* The round-headed apple-tree borer, Saperda candida; the flat-headed apple- 
tree borer, Chrysobothris femorata. + Conotrachelus nenuphar. %{ Anasa tristis. 
¢ Mytilaspis pomorum. 
