14 THE CANADIAN ENTOMOLOGIST. 



ASPIDIOTUS PERNICIOSUS, Co.mstock, and AONIDIA FUSCA, 

 Maskell: a question OF IDENTITY OR VARIATION. 



BY W. M. MASKELL, WELLINGTON, NEW ZEALAND. 



In the " Report of the Entomologist of the United States Depart- 

 ment of Agriculture for the year 1880," Professor Comstock described 

 (p. 304) an extremely injurious insect of the family Coccid^e, 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 fruit- 

 trees 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 Jose scale," and is looked on as a 

 most troublesome thing. 



An article in "Insect Life," Vol. VI., No. 5, September, 1894, 

 contains much information relative to this insect, and its occurrence in 

 various places in America since 1880. Here and there the scale appears 

 to have been found on peach, but only in small quantity ; the principal 

 victims are pear, plum, Japanese plum, apple, currant, etc., and most 

 especially pear. In a subsequent article (" Insect Life." Vol. VII., No. 

 2, p. 165) the same trees are mentioned, with the addition of Japanese 

 quince, and elm (American ?). Again, in the same publication (Vol. VII., 

 p. 285) the pear is given as the chief victim of this scale. 



In the Agricultural Gazette, of New South Wales, September, 1892, 

 p. 698, Mr. A. S. Olliff reports Asp. perniciosus in Australia on pear. 



In September, 1894, I received from Mr. French, of Melbourne, 

 some twigs of peach trees thickly covered with a scale which, in my 

 paper on Coccidft (read November, 1894; published in Transac. New 

 Zealand Institute, Vol. XXVII. ), I identified as belonging to the genus 

 Aonidia, and named Aon. fusca. 



In March, 1895, the same gentleman sent me some apple twigs with 

 many scales, which I found to be Aspidiotus perniciosus. 



Finally, in July, 1895, Mr. Olliff sent me twigs of pear, peach, and 

 apple, from New South Wales, much infested by Aspidiotus perniciosus. 



It was whilst examining these last specimens that the characters 

 which I observed in the adult females led me to compare them closely 

 with those of Aonidia fusca, and, as a result, I cannot help being con- 

 siderably perplexed, 



