37 



the bark to the sap and begin to feed. A covering scale is soon 

 formed, protecting the insect beneath, and in the fall the eggs are 

 deposited there, after which the insect dies. There appears to be 

 but one brood each year in Massachusetts. 



This scale has quite a list of food plants, including the apple, 

 pear, plum, quince, poplar, willow, ash, lilac and elm. Individual 

 trees are frequently killed by it, but it is very rare that it spreads 

 to the trees and shrubs around, killing them all, as is so often the 



Fig. 3. — Oyster shell scale: a, under side of female sciile, ghowinij eggs; b, upper side 

 of same, both much enlarged; c, female scales on a branch, natural size; d, male scale, 

 much enlarged; e, male scales on branch, natural size. The tine lines to the right of a, b 

 and d show the real length of the scales. (Howard, U. S. Dept. Agr., Yearbook, 1894.) 



case with the San Jos6 scale. It has enemies and parasites which 

 aid in keeping it in cheek, and its low annual rate of increase 

 renders it much less to be feared than the last-named pest. 



Treatment. 



Any treatment effective for the San Jose scale will also destroy 



this insect, but its life history is such as to provide an opportunity 



for easier methods as well. As all the 3'oung hatch about the 



same time — about the first of June — two sprayings at this 



