70 REPORT OF No. 19 



The Oah Petiole Gall (Andricus petiolicola). 

 This is a midrib or petiole gall. It is hard and woody and projects on 

 one side, generally on the lower. It averages 1.2 cm. by .7 cm. and 8 m.m. 

 wide. It contains several cells, lined with hard white tissue which in some 

 cases are arranged like the seed cases in a core of an apple. In each of 

 these is a small white larva, apparently legless, and covered with a viscid 

 transparent secretion. The gall is green or red and more or less roughened 

 on the outside. Occurs on White Oak (Quercus alba and Quercus prim- 

 oides). Common. 



Rose Root Gall (Rhodites radicuni). 



A smooth, irregularly rounded, brownish swelling upon the root of the 

 Wild Rose. Reddish brown in color, quite |ight and pithy in structure 

 and containing numerous cells. From 3 to 5 cm. in diameter. Occurs on 

 roots of Wild Rose (Rosa sp.). Not common. 



Spiny Ball Gall on Wild Rose Leaf (Rhodites hicolor). 



This is a very beautiful little gall which is rare in this vicinity. It is 

 monothalamous and is formed upon the leaf of the wild Rose and sometimes 

 all the leaflets are transformed in this way. The gall is a thin-walled ball, 

 red or green in color and covered with short spines. It is monothalamous and 

 cpntains one small larva about | m.m. long. The gall is about .75 cm. in 

 diameter. The wall is about f m.m. thick. There is no opening. The 

 inside is quite smooth. Occurs on Wild Rose (Rosa sp.). Not commoii. 



Rose Stem Gall (Rhodites globulus). 



This gall is found upon the stem of the Wild Rose. It consists of an 

 abrupt corky enlargement of the stem. It is about 2-2.5 cm. in length and 

 about 1-1. '5 cm. in width. It is quite smooth on the outside, not at all 

 pubescent, and green or red in color. A single long chamber runs longi-. 

 tudinally through the gall about 3 m.m. in diameter and irregular in shape. 

 In this are small larvae about 3 m.m. in length. The larva is dark grey 

 with a lighter head and tail and is legless. Occurs on Wild Rose (Rosa 

 Carolina). Not common. 



Mossy Rose Gall (Rhodites rosa'). 



It is composed of a ma'ss of hard, small cells clustered around a branch 

 or twig. These cells are covered with a dense thick mass of green filaments 

 which grow from them. The gall is monothalamous and from 1.5-2 cm. in 

 diameter. Occurs on Wild Rose (Rosa Carolina). Common. 



The Larger Oah Apple (Amphibolips confluentis). 



Thin walled and globular, about 4 cm. in diameter. Exterior surface 

 smooth (not pubescent) and somewhat irregular. Interior filled with a 

 spongy mass of fibres, very loosely attached to the exterior but tightly at- 

 tached to an interior woody cell in which the larva lives. Green in the early 

 part of the season, later turning brown and brittle. Generally produced on 

 the upper part of the leaf from the end of one of the veins. Occurs on Red 

 Oak (Quercus rubra) and other closely related species. Common. 



Hedgehog Gall on Oah (Acraspis erinacei). 



A round or oval gall growing on the midrib of the leaf. About 1 by 

 5 cm. The gall is white or yellowish and covered with fine bright pink or 

 red spines about 1-2 m.m. in length. Attached to the leaf at a point about 



