lOO 



NEW YORK STATE MUSEUM 



These latter remain quiescent nearly lo montlis in the year and 

 it is in this stage that we have the best chance of controlling the 

 insect. 



It is possible that thorough spraying with kerosene emulsion or 

 a whale oil soap solution in early spring before there was the 

 slightest signs of hickory foliage would result in the destruction 

 of many of the winter eggs. It is very probable that a treatment 

 with a standard lime-sulfur wash would be much more effective 

 than kerosene emulsion or a whale oil soap solution, particularly 

 if it was applied very thickly, because this material possesses active 

 insecticidal properties for some time, and even if it was not strong 

 enough to kill the eggs at the outset, something which is rather 

 doubtful, it might possibly destroy the young plant lice upon 

 hatching and thus prevent further injury. Unfortunately this 

 method of control can be applied in a practical way only to small 

 trees as a rule and it should be supplemented where possible by 

 cutting off the green galls and destroying them before any of the 

 insects escape, since this species appears to be somewhat local in 

 its work. 



Spindle-shaped elm gall (Pemphigus u 1 m i f u s u s Walsh) . 



Specimens of this rare gall were 

 received from Mr C. L. Williams 

 of Glens Falls, N. Y. July 7, 1905. 

 The galls are confined to the upper 

 surface of the leaf and are usually from 

 y.\ to y2 inch from its free edge, origin- 

 ating in a clear area between the veins. 

 The galls range in size from /4 to ^ 

 of an inc'i in length and have a very 

 narr^- neck with a widely dilated 

 body. The specimens transmitted vary 

 in color from pale yellowish white to 

 dark brown. The latter appear to have 

 attained maturity and several at least 

 had ruptured near the base, thus al- 

 lowing- the occupants to escape. An 

 examination of several of the green 

 galls shows that the walls are moder- 

 ately thick, each inhabited by a solitary 

 stout, wingless, purplish black plant louse. There were no signs of 

 rapid multiplication. 



Fig. 12 Spindle shaiied elm galls on 

 leaf, much enlarged (Original) 



