THE CANADIAN ENTOMOLOGIST. 251 



of the occupants of galls. The living feeding upon the living, without 

 pain or apparent inconvenience, and all this while in the larval form. 



Shall we say the relations are physiological and not pathological in 

 any sense ? The living plant fed upon by the gall-producer and the 

 inquilines, these by the primary parasites, and these again by the second- 

 aries. A harmonious system of eat and be eaten, and strangely at the 

 same time the eater is often the eaten, and although, in the end, it means 

 death to the eaten, it is not so shocking to our sensibilities as the cat 

 enjoying the agonies of the tortured mouse or the sportsman triumphing 

 over the " fluttering gory pinion." 



Rhabdophaga siliqua, Walsh ; Cecidomyia salix-siliqua, Walsh. 



Galls nearly terminal on upland willow twigs ( Salix humilis), flask 

 or rather horn-shaped, usually curved," ending above in a slightly-curved 

 beak, out of which the occupants emerge. The galls are aborted buds, 

 and when overtopped by the twigs lie closely to them. The galls 

 are often striated, of a greyish-green colour, corresponding to the colour 

 of the twig, and rarely bear a few leaves. The average of 30 galls col- 

 lected in the fall of 1882 was 7x12 mm. From this lot collected Dec, 

 1882, the producers, R. siliqua, emerged May, 1883, and towards the end 

 of June numerous specimens of the Chalcid parasite, Torymus splendidus, 

 emerged. Walker described and named this beautiful Torymus from 

 specimens collected at Hudson's Bay, which may be accepted as pre- 

 sumptive evidence that this gall may be found there. In any case the geo- 

 graphical range is large. This gall is more or less common over Ontario 

 where Salix humilis is found ; it is more or less common in North York; 

 Muskoka, Algonquin, Temigami, and along the Montreal River on Salix 

 discolor. During the fall and winter seasons of 1886 and 1887, I 

 received several parcels of this gall from Northern Manitoba, collected 

 from some species of willow ; they were in every particular similar to 

 Toronto galls, but no producers emerged from them. In the spring of 

 1887 I received from Mrs. W. A. Ducker a parcel of galls collected at 

 Banff, Alta., from a species of willow ; in size and shape they were 

 identical with Toronto and Manitoba galls. Mrs. Ducker wrote : " The 

 galls are on the ends of willow branches. I do not know the willow, but 

 both willow and galls are common all around Banff." Producers emerged 



