New York Agricultural Experiment Station. 349 



the eggs or the young larva? when they first appear, so that the 

 necessary steps can be taken to check the insect before serious in- 

 jury is done. 



Importance in the nursery. — This saw-fly is occasionally found 

 in the nursery, where it may do much injury to the young black- 

 berries and raspberries. The larva feed upon the new growth 

 of the young tips after first devouring the leaves, and hence may 

 do serious injury by checking the early growth of the plant. 



food plants. 



As its name indicates, this species feeds principally upon the 

 raspberry. In a large field of raspberries near the Station where 

 several varieties are under cultivation, and where the insect has 

 been very abundant for nearly four years, the Shaffer bushes have 

 suffered most injury each season. In addition to the raspberry, 

 the blackberry and dewberry are subject to attack 



INJURY TO THE PLANT. 



The first injury is caused by the female, which, as stated in 

 detail on another page, deposits her eggs on the under side of the 

 leaf, just beneath the cuticle. At first no apparent injury results, 

 but within a few days the upper surface of the leaf immediately 

 over the egg turns light green, and finally a light yellow color, the 

 tissue becoming dry and somewhat withered. Thus a leaf in 

 which a number of eggs have been placed soon becomes distinctly 

 spotted and hence is easily detected. (Plate XXVI, Fig. 4.) 

 Where a large number of eggs have been deposited on a single leaf 

 nearly the whole leaf becomes lighter in color and appears some- 

 what wilted. This is a matter of importance to the grower, for 

 by the spotted leaves one may be made aware of the presence of 

 the immature brood before the more serious injury caused by the 

 young larvae takes place. 



Injury to the leaves and new canes. — The first evidence of the 

 work of the larva? upon the leaves is the small irregular holes 



