EXPERIMENT STATION REPORT. 591 



THE COTTONY MAPLE SCALE. 



Piiliinaria innumcrahilis Kathv. 



General Observations.* 



This insect derives its name from the cottony covering that it 

 secretes for its eggs, which are deposited beneath the posterior portion 

 of the body. While it has l)een found infesting grape, Virginia 

 creeper {Ampelopsis quinquefoUa) and other plants to some extent, 

 it occurs most commonly on the soft or silver maple (Acer sacchar- 

 imim), and in XoWJersey is found almost exclusively on that species. 

 As with many other injurious insects it occurs more plentifully some 

 years than others, and sometimes becomes a real pest. This was the 

 case in 190-i, when it was unusually al)undant at Montelair, Newark 

 and several other points, and seemed likely to be as plentiful in 1905. 

 Although the insect has been briefly treated in several of the reports 

 and bulletins, this occurrence offered a good opportunity for a careful 

 study of its habits and life history, as well as its natural checks. 

 Accordingly, in Fel)ruary, 1905, infested localities were visited and 

 the condition of the trees and insects was noted, while throughout the 

 spring and summer twigs were collected and received from several 

 points, though principally from Montelair, through the kindness of 

 Mr. Malcolm H. Smith and Mr. W. D. Kearfott. 



February 2d, infested twigs were collected in Newark to deter- 

 mine the condition of the hibernating insects, which were mostly 

 scattered along the under side, with now and then a few on the upper 

 surface. They usually lay parallel with the twigs, extending from 

 near the tip back on to the older growth. In some "places somewhat 

 torn, cottony masses, the remains of the previous year, were observed, 

 and under the edges of several of these a few very small, parasitic 

 larvae and pupse, in rather hard cocoons, were found. In all some 

 sixteen twigs were examined, averaging about a foot in length, with 

 some sixty insects on each, one-third of which were alive and two- 

 thirds apparently dead. These hibernating insects Avere small and 

 dark brown in color, about one-sixteenth of an inch in length and 

 about half as broad. They were oval in outline, a little convex, with a 

 slight ridging along the center. A few smaller, darker and more 



* This narrative is by Mr. E. L. Dickerson, who made the direct observations 

 under my direction. 



