94 THE REPORT OF THE No. 19 



part of an adjoining leaf or leaves. It seems always to start in the axil of 

 a leaf. The stem gradually thickens at the affected part to almost three 

 times its normal size and does not continue to elongate in this part as it does 

 above and below it ; so that in a space of 1 to 2 inches where we should nor- 

 mally find not more than four leaves, we here get eight or nine, some of them 

 dwarfed and distorted. Moreover the stem at this point, instead of growing 

 straight out in its normal direction, often becomes distorted and bent in 

 another direction, sometimes nearly at right angles to its former course, and 

 then coming back to its first direction grows on parallel to it. The gall 

 itself looks like a very irregular tubercular mass of closely packed small 

 reddish-green protuberances about i inch high. These irregular masses 

 in some places encircle the stem, in others are chiefly on one side of it though 

 often extending to the basal part of the leaves. Sometimes the masses are 

 so close as to be continuous, at other times they are J inch or more apart. 

 The whole of the affected part of the stem is usually from | to 1| inches in 

 length, and the irregular mass when surrounding the twig makes the total 

 diameter ^ to 1 inch. Later in the season and during the winter the gall is 

 black and the part of the stem above it in most cases dies. There is usually 

 but one gall on a stem, but sometimes a second or third occurs at some dis- 

 tance below it. This gall is somewhat similar to what I have called the 

 unsightly Willow Gall, described above. It occurs on the American Aspen 

 (Populus tremuloides). Rather rare. 



Speck Gall of Chokeberry (Eriophyes sp.) 



This gall, as the name indicates, is a very tiny, speck-like structure, 

 usually much smaller than the head of a pin but occasionally a little larger. 

 It is visible equally on both sides of the leaf and, when mature, is of a brown 

 color. In none of the numerous specimens observed did it extend more 

 than .5 mm. beyond the surface. The gall resembles very much a species 

 of Eriophyes gall found on the hawthorn. Numerous galls, scattered here 

 and there throughout the parenchyma, are usually found on each infested 

 leaf. They occur on the chokeberry. (Pyrus melanocarpa) . Common in 

 Muskoka. 



Grape Leaf Wart Gall {Eriophyes sp.). 



This is a small semi-circular, or sometimes nearly circular, wart-like 

 gall situated along the veins of the leaves. It is about 2 mm. in diameter 

 and only very slightly elevated beyond the plane of either surface of the 

 leaf. The upper surface is fairly smooth and slightly paler in color than the 

 rest of the leaf. The under-surface is of much the same color and kind 

 of surface as the underside of the leaf, but it has a tiny white nipple in the 

 centre, and around all the gall, except the part touchiiig the vein, there is 

 a distinct depression or furrow. There are often several galls on a single 

 leaf. They occur on the Wild Grape {Vitis cordifolin). 



Pin Cherry Gall {Eriophyes sp.). 



Oblong or club-shaped, reddish projections scattered over the leaves, 

 somewhat irregular in outline and pubescent, 3-4 mm. long .5-1 mm. dia- 

 meter, being broadest at the top. Generally borne on a little curved pedun- 

 cle-like portion which is about 1 mm. long and lighter in color. 



In conclusion the writer desires to express his thanks to Dr. E. Porter 

 Felt, Mr. William Beutenmuller, and Prof. Bethune who have most kindly 

 aided in the preparation of this paper. Especial recognition must be given 

 to Mr. L. Caesar, who has assisted in describing many of the species. I am 

 much indebted to Mr. W. R. Thompson and Mr. C. D. Jarvis, who have 

 furnished the photographs for this paper. 



