Hollister, W.O. 1920 Distribution of shade tree insects in 1919.. Journal of Economic Entomology 13: 143-147.

Notes: Scale species mentioned include Phenacoccus acericola, Lepidosaphes ulmi, Chionaspis pinifolia, Toumeyella liriodendri, Chionaspis americana, Gossyparia ulmi and Asterolecanium variolosum.