18 



THE EEPORT OF THE 



No. 36 



a large number of the galls and kept them during the winter under as nearly 

 natural conditions as possible. A number pupated a couple of inches below the 

 surface of the soil in the breeding jar, and several adults emerged between June 

 3rd and 10th, S. A. Eohwer, Washington, D.C., to whom specimens were sent, 

 has not yet published his description, but has sent me a manuscript copy of it. 

 The species which has been named Euura cosensi n. sp., is said to be closely con- 

 nected with Euura nodus Walsh, a form that produces stem galls on Salix 

 longifolia Muhl. From this species it may readily be differentiated by the shape 

 of the sheath and the different sculpture of ihe head. 



The following list includes all the sawfly gall producers as far as reported 

 from this locality. 



Fig. 1. — Euura cosensi Rohwer, a sawfly gall on the leaf petiole of 



Salix humilis Marsh. 



Euura cosewst Eohwer. 



Host, Salix liumilis Marsh; 



The gall, which is produced on the leaf petiole, is conoidal in shape with a 

 long tapering point, towards the blade of the leaf. 



Euura gemma Walsh. 



Host, Salix humilis Marsh. 



In this species, the gall is formed by the abnormal swelling of a lateral bud. 



Euura ovum Walsh. 



Host, Salix humilis Marsh. 



An elongated oval swelling on one side of a twig constitutes the gall in this 



case. 



The three preceding species are common in and near Toronto. 



Euura serissima Eohwer. 



Host, Salix serissima Fernald. 



