^-TRANSACTIONS OF THE AMERICAN ENTOMOLOGICAL SOCIETY VOLUME XLIV NEW APHIDIDAE FROM CALIFORNIA ^ BY ALBERT F. SWAIX University of California Citrus Experiment Station, Riverside, California It is the purpose of this paper to describe several new species of A phididae taken during the past few j'cars in CaHf ornia. Many of these species have been taken by the writer in his study of the plant lice during the past three years, while some others have been obtained from various people in different parts of the state. The species recorded here represent collections made in the vicin-ity of Sacramento; in the San Francisco Bay region, particularh' in the vicinity of Stanford Universit}' and in Berkeley; and in Southern California, particularly in San Diego, Riverside, and Ventura Coimtics. Cotype specimens of all the species are in the writer's private collection in Riverside and in the collection of the University of California. Berkeley. Myzocallis davidsoni new species (Figs. 1, 1.5, 34, 35, 36.) In the fall of 1915 the writer found a large infestation of a species of Myzocallis on Quercus peduncidata in Berkelej'. On examination this proved to be the same species which had been taken several times on various species of chestnuts (Castanea spp.) and considered as Calap/us castaneae (Fitch). It is a com-mon species in the San Francisco Bay region, having been re-ported several times from Berkeley, Oakland, Stanford Universitj^ 1 Paper No. 41, University of California, Graduate School of Tropical Agri-culture and Citrus Experiment Station, Riverside, California. THAXS. A.M. ENT. SOC. XLIV.