Amphibolips confluens, Harris, host Quercus velutina, Lam. Amphibolips inanis, O.S., host Quercus rubra, L. These species are the common large " oak apples." While very much alike in external form, the parenchyma zone in the former consists of a dense mass of interlocking fibres, while only a comparatively small number of delicate straight strands constitutes it in the latter.
Andricus singularis, Bassett. Host Quercus rubra, L. In size and external form this gall closely resembles Dryophanta palustris, O.S., but its larval chamber is supperted at. the centre of the gall by radiating bands of tissue.
Andricus piger, Bassett, host Quercus velutina, Lam. Andricus petiolicola, Bassett, host, Quercus alba, L. These galls are both produced by the swelling of the midrib or petiole, but can be distinguished by means of the different hosts.
Aulacidea nabali, Brodie. Hosts Prenanthes alba, L., and Prenanthes altissima, L. A large spherical swelling of the base of the stem of two of our rattlesnake-roots, usually just below the ground.
Aulacidea tumida, Bassett. Host Lactuca canadensis, L. This species produces an elongated swelling of the stem of the wild lettuce, situated near its summit, usually in the panicle.
Biorhiza forticornis, Walsh. Host Quercus alba, L. The individual gall is almost spherical in shape and has suspended at its centre by radiating fibres