28 



iliar to us all. Sometimes as many as twenty of these galls are seen on 

 one leaf. They result from the operations of the fly Pontania (Messa) 

 hyalina Norton. 



Some 3^ears ago I sent specimens of the galls of this species and of 

 the perfect insects to an Euglish hymenopterist, Mr. EdwardI A. Fitch. 

 He wrote to me from Maiden, Essex, on the 29th of May, 1885, saying- 



"The saw-fly I have but little doubt is identical witji our British 

 Nematus gallicola West (VallisneriiHart) as far as I can judge from the 

 female and gall sent. 



The larvae of the species dwell in the galls till the approach of win- 

 ter, each finding its habitation to be a fortalice \vell stored with food. 

 When the leaves fall, the larvae jbite openings to the outer air, descend in- 

 to the earth, and there spin for them-selves cocoons, in which they remain 

 till the A\4nter is past. The perfect flies appear when the leaf buds of 

 the w^illow are about to open. 



I have shown in the 3rd Annual Report of our Society that the Eng- 

 lish sparrow is a foe to this saw-fly. 



Of other species that affect the willow I have taken two new kinds, 

 in Quebec Province, viz: — Petronus Harrington i Marlatt, and 

 Pteronus fylesi Marlatt. Both are fully described in Marlatt's 



Revision of the Nematinae of North America, pp. 53 and 54. 



The largest of our saw-flies is Cimbex americana Leach It 



is an inch and three quarters in expanse of wings, and five-sixths of 

 an inch in length of body. The typical insect has head, thorax and legs of 

 a dark brown, abdomen chestnut-colored, antennae and feet yellow. Its 

 wings are clear but all have a light-brown shade along the hind margin. 

 The venation of the ^vings is brown and very distinct. 



The larva of this insect feeds on the w^illo^v and other trees. It, is an 

 inch and a half, or more, long, of a pale greenish yellow, w^ith a 

 black dorsal line and black spiracles. It has the habit of curling itself 

 helix fashion;i and in this form it may often be found at the foot of its 

 food tree. This larva has 22 legs — six more than the caterpillar of a but- 

 terfly. 



The num'bers of Cimbex americana are kept down by a large and 

 handsome ichneumon fly, Opheltes glaucopterus I/inn. 



No less than eight named insects have been related by Cresson in 

 his "Synopsis of the Hymenoptera of America, North of Mexico" to 

 CHmbex americana. One of them, Climbex ulmi Peck, is fully de- 



scrijjed in Harris's "Insects Injurious to Vegetation," p. 519. It is a very 

 handsome insect. Peck found it feeding upon the Elm ( Ulmus ) but that 

 is not it|s only food-plant. I found it on the Paper Birch ( Betula papy- 

 racea Ait ) season after season at South Quebec. 



