In the “Report of the Entomologist of the United States Department of Agriculture for the year 1880,” Professor Comstock described (p. 304) an extremely injurious insect of the family Coccidæ, to which he gave the name Aspidiotus Perniciosus, or “the pernicious scale,” and he stated that this insect attacked a very large number of deciduous fruittrees in California, “excepting peach, apricot, and black tartarean cherry.” Later, this pest was observed, described and discussed by many persons interested in horticulture, and in America it is generally known by the trivial name of “the San José scale,” and is looked on as a most troublesome thing.