The expts. reported were designed to determine the role of plants and animals as food for G. punctipes and G. pollens. Cage expts. conducted at the Modesto, Calif., laboratory showed that these 2 spp. could not live on insects alone or on plants alone, but require a combination of the 2. Apparently, the plants served only as a source of water. With plants available, Geocoris lived equally well on beet leaf-hoppers (Eutettix tenellus) alive, dead and preserved by refrigeration, or dead and air dried. The mortality was increased if the leafhoppers furnished as food had been treated in ether, although even then some sustenance was available. Presence of dead leafhoppers did not reduce feeding on live leafhoppers. During the summer Geocoris adults consumed about 1 adult leafhopper every 2 days. The predators consumed eggs of the beet leafhopper, which were laid in plant tissue. The av. daily consumption by G. pollens during the summer was 2.5 eggs per day for [male][male] and 4 eggs per day for [female][female]. It would be practicable to experiment with these predators as a factor of natural control.