744 



NEW YORK STATE MUSEUM 



are enough individuals in one gall to give an empty one a very 

 characteristic appearance on account of the whitish, projecting 

 pupal cases. A gall is represented at pi. 4, fig. 1. 



Adult flies were obtained from May 22 onward, from material 

 received on the 10th, and on the 31st a parasite was bred. This 

 was kindly identified by Dr Ashmead of the United States 

 national museum as Tridymus salicis Nees, a species 

 recorded for the first time in America. Tridymus metal- 

 lic u s Ashm. was bred in small numbers from galls received in 

 the spring of 1902 and Polygonotus salicicola Ashm. 

 was reared in numbers. This abundance of parasites leads us to 



hope that natural agents will 



soon control this pest. Twigs 

 received June 3, 1901, directly 

 from the willow plantation 

 had disclosed some flies, 

 showing that the period of 

 emergence extends over a 

 number of days. Mr Peck 

 further states that Mr Wil- 

 son has been in the habit of 

 opening cases of imported 

 stock near the block of in- 

 fested willows; so it would 

 be comparatively easy for 

 them to become infested. 



Carpenter moth, Prion- 

 oxystus robiniae Peck. 

 This is a serious enemy to 

 maple, oak and ash trees in 



Fig. 17 Work of carpenter moth caterpillars, 

 pupal case and adult (original) 



certain sections of New York state. Its destructive work 

 at Ogdensburg was brought to my attention by Miss Mary 

 B. Sherman of that place, and through her some inter- 

 esting examples of the borers' work in sugar mapletrees 

 were secured. One third of a section of a tree about 15 inches 

 in diameter was fairly riddled with the large burrows of 

 the caterpillar of this insect. It was so abundant as to 



