164 



MONTANA EXPERIMENT STATION. 



the plant settle down and begin feeding. Other broods follow, th$ 

 number varying with the latitude. 



The female scale is circular about one-twelfth of an inch in diam- 

 eter when full grown and only slightly convex. It is gray or black- 

 ish sometimes with a yellowish t-'nge. 



The mature male is oblong-oral, its length being about one-half 

 the diameter of the female scale, black or grayish and having in the 

 center a nipple-like prominence. See the accompanying figure. 



It is a source of wonder to many that an insect so small as the 

 San Jose scale can overcome a tree. The explanation is found in 

 the fact that the life of the tree exists just under the bark upon 

 which the countless numbers of scales settle inserting their beaks 

 into lie vital tissues just under the SMr:.!:^. While these insects 



Fig. 13. San Jose Scale: a, adult female showing very long sucking setae; 

 b, anal plate showing characteristic ornamentation of edge; greatly enlarged. 

 (Howard and Marlatt, Bulletin 3, Div. of Entomology, U. S. Dept. of Agr.) 



