1907 ENTOMOLOGICAL SOCIETY. 93 



The Unsightly Willow Gall, (Eriophyes sp.) Plate D, fig. 5. 



This far-from-beautiful gall seems in most cases to spring from the axils 

 of the leaves; occasionally, however, it is formed on the leaf itself. Often 

 several galls are formed near the end of a twig. In these cases probably 

 they started in the axils of the leaves which were subsequently absorbed into 

 the galls themselves. Where the galls occur near the terminus of a twig, 

 they are usually thickly clustered and encircle the stem, whose longitudinal 

 growth becomes checked in such cases. The galls vary greatly in size and 

 compactness of structure. Occasionally one is found that has the appearance 

 of a small rosette, about i to 1 inch in diameter, composed of tiny, thickened 

 leaflets covered with a whitish pubescence, the basal half of the leaflets being 

 grown together and only the upper half being separate. In other cases a 

 number of smaller galls are loosely clustered into one fairly large group, often 

 an inch or more long. In other cases only a single diminutive gall is found. 

 The galls, especially where loosely clustered, look considerably like the flower 

 or fruit clusters of Lamb's Quarter {Chenopodium album), or like a very 

 irregular whitish green fungus growth. In fall and winter they become 

 grayish black and, where numerous, disfigure the tree considerably. They 

 occur on the Scrub Willow {Salix sp.). Hare, except in a few localities. 



Chestnut Leaf Gall {Eriophyes, sp.). 



A small gall projecting from both sides of the leaf. When found along 

 the side of the leaf-vein it is hemispherical, elsewhere is more or less spherical. 

 The diameter is about 2 to 3 mm. Somewhat the larger half of the gall is 

 on the upper surface. The color at first is green, but turns brown when 

 mature. Monothalamous. Occurs on the Chestnut (Castanea sativa). Com- 

 mon. 



Convex Gall of Poplar {Eriophyes sp.). Plate D, fig. 3. 



This gall has the shape that one imagines would be formed if he were 

 to press the tip of the little finger, or of some round instrument, against 

 the lower surface of the leaf and, without breaking the tissues, were to cause 

 them to yield until there was a decided depression on the lower surface and 

 a corresponding bulge on the upper. There is practically no thickening of 

 the tissues of the leaf or change in color except that the under surface of 

 the gall is orange yellow. The depression varies in size, being about 4-12 

 mm. in diameter and 2-5 mm. in depth. Occurs on Lombardy Poplar {Popu- 

 his dilatata). Rare. 



Walnut-leaf Wart Gall {Eriophyes sp.). 



A warty protuberance chiefly on the upper surface of the leaf, con- 

 stricted at the base, about 2-5 mm. high and 2-3 mm. thick in its widest 

 part ; surface usually very uneven with many depressions and elevations ; 

 color green; texture of outer part somewhat pulpy but most of the interior 

 is composed of a mass of loosely woven silvery fibres or strands. This gall 

 resembles greatly the Elm-leaf Wart Gall {Eriophyes ulmi), but has a 

 rougher surface at the top and is not frequently found on the under sur- 

 face of the leaf. Occurs on black walnut {Juglans nigra). Common. 



Walnut-Cushion Gall {Eriophyes sp.). Plate D, fig. 2. 



Large and somewhat cylindrical in outline. Found on the lower por- 

 tion of the petiole (in some cases the pul villus is affected). A green solid 

 swelling clothed by a dense fur-like covering of short reddish hairs about 1 

 mm. in length. The galls usually appear on the upper side of the petiole, 

 with the edges overlapping. 8-10 mm. long and 4-8 mm. broad, but varying 

 considerably in size. On black walnut {Juglans nigra). 



Unsightly Poplar Stem-gall {Eriophyes sp.). 



This is one of the most irregular and unsightly of all our galls. It is 

 found on the stem of young twigs though sometimes it extends to the basal 



