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NEW YORK STATE MUSEUM 



Studied by Mr Theodore Pergande, who had been interested in the insect 

 for over 20 years, and in 1899 succeeded in completing its Hfe history. 

 The following is an abstract of his detailed notice. 



The rapidity of growth depends on the season. The galls usually 

 begin to appear in the latitude of Washington D. C. about the middle of 

 April, attaining full growth toward the end of May. Young stem mothers 

 hatch a week or more before the leaves appear and frequently assemble in 



d 



Fig. ^12 Horm 

 twig and bud with yount 

 ^— young stem mother; c= 

 f-rostrum; y— waxy rodi 

 (After Pergande, U S. Dep't Ag: 

 Tech. Ser. 9, 1901) 



considerable numbers awaiting the unfolding of the buds. The plant lice 

 settle along the midrib and the lateral veins of the unfolding leaves, and 

 soon cause a pale yellowish green discoloration on the upper surface. The 

 few days old gall appears as a small blisterlike swelling on the upper side. 

 It develops rapidly and in May is quite convex or slightly conical, with the 

 opening on the under surface nearly closed. The young galls are greenish 

 yellow with the tip more or less purplish. The fully developed gall is 

 shown on plate i, figure 7. 



The dormant season is passed as a winter ^^'g deposited on the 



