Page:Popular Science Monthly Volume 5.djvu/175

Rh ), especially certain small dark-brown species belonging to the genus Scymnus, and whose young, thickly covered with white and evenly-shorn tufts of a cottony secretion, are frequently found at their good work within the galls. Pillowing these may be mentioned, as auxiliaries, certain Syrphus-fly larvæ, which, being blind, go groping about among the eggs and young lice, which they seize and suck to

death. Also certain orange larvæ of a smaller two-winged fly (Leucopis); a few genuine bugs (Heteroptera), and notably the Insidious Flower-bug (Anthocoris insidiosus, Say, Fig. 6), and certain smaller Hymenopterous parasites.

The enemies known to attack the Phylloxera underground are, naturally enough, fewer in number. In one instance I have found a Scymnus larva at the work six inches below the surface, and there is a Syrphus fly (Pipiza radicum, W. and R., Fig. 7) whose larva lies underground and feeds both on the apple-tree-root louse, and on this



grape-root louse. Wonderful indeed is the instinct which teaches the blind larva to penetrate the soil in search of its prey; for the egg must necessarily be laid at the surface. But, though the underground enemies of its own class are few, I have discovered a mite which preys upon this root-inhabiting type, and which renders efficient aid in