86 THE REPORT OF THE No. 19 



A dense mat of brown hairs growing in large patches upon the under 

 sides of the leaves. Oak Hair Gall — Eriophyes sp. — (Undescribed) — Quer- 

 cus sp. 



A dense, white pubescence upon the under side of the leaves causing 

 a distortion and folding of leaf blade. The pubescence is inside the fold, 

 forming the lining of the gall. Oak Fold Gall — Cecidomyia Niveipila, O.S. 

 Quercus rubra. 



Green or brown, narrowly oval, inflated galls produced along the veins 

 on the under side of the leaves. The surface of the gall is netted with veins. 

 Oak Vein Gall — Cecidomyia quercus Tnajalis O.S. — Plate E., fig. 5. Quer- 

 cus rubra. 



Pale red, saucer-shaped galls in clusters on the Tinder surface of the 

 leaf. Oak Spangles — Cecidomyia poculum, O.S. Quercus alba. 



Small, bright red galls, joined to the leaf by a small portion of the sur- 

 face, 80 that they are easilj detached without injuring the leaf. The sur- 

 face of the gall is netted with innumerable fissures between which are small 

 elevations with very short spines. When on the under side of the leaf, the 

 gall is white in color. Oak — Ad,raspis macrocarpa — Quercus macrocarpa. 



White, furry, hemispherical mass varying from 4-11 mm, in diameter. 

 This is composed of innumerable fine, woody fibres to which are attached 

 small, round kernels. The Larger Furry Ball Gall — AndVicus lana — Plate 

 E., fig. 1. Quercus macrocarpa. 



Small, button-like enlargements upon the upper and lower surfaces of 

 the leaves. Button Gall — Neuroterus umhilicatus (Bass) — Plate B., fig. 6. 

 Quercus macrocarpa. 



Small, dithalamous, pea-shaped gall on the upper side of the leaf. The 

 surface is fissured or netted with depressions between which are elevations. 

 Oak Pea Gall — Cynips Pisum — Quercus alba and macrocarpa. 



Hard, woody gall occurring on midrib or petiole. Green or red in 

 color and more or less roughened on the surface. Oak Petiole Gall — 

 Andricus petiolicola. 



Large globular gall about 4 cm, in diameter. Exterior surface smooth 

 and somewhat irregular. Interior filled with a spongy mass of fibres, very 

 loosely attached to the wall of the chamber. The Larger Oak Apple Gall — 

 Amphibolips confluentis, (Harr.) — Plate E., fig. 2. 



Small, pale-green, wart-like gall situated in the parenchyma of the leaf 

 and protruding beyond both surfaces but chiefly beyond the lower. Inside 

 are two or three seed-like, oblong kernels, kept in position by white fila- 

 ments. Oak Wart Gall — Andricus futilis, O.S. — Plate B. fig. 4. Quercus 

 macrocarpa. 



Round or oval galls growing on the midrib of the leaf. The gall is 

 white or yellowish and covered with fine bright pink or red spines about 

 1-2 mm. in length. Oak Hedgehog Gall — Acraspis crinacei — Plate R. 

 fig. 1. Quercus alba. 



Small spherical gall about 3 mm. in diameter upon the veins of the 

 leaves upon the under side of the leaf. It is thickly covered with fine short 

 hair which forms a cushion all around it. Oak Furry Ball Gall — Neuroterus 

 floccosus — ^Plate R. fig. 2. Quercus alba. 



Large, smooth, spherical galls from 2-3 cm. in diameter occurring on 

 the under side of the leaves. The small, spherical, larval cell within the 

 cavity is held in position by a comparatively small number of filaments 

 which radiate from it to the surrounding walls. Empty Oak Apple Gall — 

 Amphibolips inanis (O.S.). Quercus rubra. 



