SOME DESTRUCTIVE SCALE INSECTS OF NEW YORK 273 



In Fig. 2 of Plate III (after Wakh and Biley) the scales and egg- 

 masses are shown on osage-orange as Lecanium Madura, and on 

 maple as L. acericola, but both now referred to P, innumerabilis. 



This scale had become very abundant upon the maples in the 

 streets of Brooklyn in 1890, and was reported as having killed a 

 large number of the infested trees.* In 1884, it was excessively 

 abundant and quite destructive over the larger part of the State of 

 Illinois. Further particulars of it, and available remedies, may be 

 found in the Sixth Rejjort on the Insects of New York, 1890, pp. 

 141-147. 



The Plum-tree Scale-Insect 



In Plate IV, the plum scale is shown, — an apparently new and 

 destructive plum pest, which has during the past year made its 

 appearance in different localities in the State of New York, par- 

 ticularly in its western portion. Examples of it were received by 

 me on May 14th and loth from Dr. Collier of the Geneva Agricul- 

 tural Experiment Station, and from C. M. Hooker and W. C. 

 Barry, of Kochester. No record could be found of its previous 

 occurrence as infesting the plum. Upon submitting it to Prof. T. 

 D. A. Cockerel], of Las Cruces, New Mexico, who has made special 

 study of scale insects, it was determined by him, with a possible 

 doubt, as Lecanium juglandis Bouche. This determination has 

 not been accepted by some entomologists, while as an explanation of 

 difference of opinion in regard to it, it has been suggested that two 

 closely resembling species are associated on the infested trees. 



The species of Lecanium are large, conspicuous scales, as may be 

 seen covering the branch in the figure, approaching a half globe in 

 form, and in the season of reproduction, containing within their 

 capacious bodies a very large number of eggs — a thousand, or it 

 may be two thousand or more. From their rapidity of multiplica- 

 tion they may prove very injurious to the trees that they infest, but 

 fortunately their size, and their tenderness during a portion of their 

 existence, exposes them to parasitic attack, and to destruction from 

 certain weather conditions. They are amenable to treatment with 

 kerosene emulsion, and to the methods which will be recommended 

 for the destruction of the San Jose scale. 



Eighth Report on the Insects of Sen* York, 1893, page 177, 

 35 



