62 REPORT OF No. IS 



Eriophyes sp. It differs from the frost mites on Hard Maple and Beech, 

 in that it does not consist of a mass of spherical granules, but of a mass of 

 tangled threads which under the lens are seen to be arranged in very beauti- 

 ful star-like clusters. The mites are easily found among these. The patches 

 are found on the under side of the leaves betwen the ribs. Occurs on Rock 

 Elm (Uhnus racemosa). Common 



EnopJiyes sp. The structure of this frost mite gall is much the same as 

 that of the red frost mite, but the mass of excrescences is thicker, white in 

 color and produced upon the under side of the leaf. Occurs on Hard Maple 

 (Acer saccliarum). Common. 



Eriophyes sp. The gall consists of a mass of tangled white vegetable 

 hairs. The growth is very much the same in general appearance as the one 

 producing the "frost" and "down" on Eock Elm and Beech. The mites 

 are quite small and difficult to locate, as they are much the same in color as 

 their surroundings, and remain down in the lower part of the gall near the 

 leaf. The gall is found on the lower side of the leaf, a common place is in 

 the axils of the veins. Occurs on Mountain Maple {Acer spicatum). 

 Common. 



Eriophyes sp. The work of this mite is very commonly seen. It appears 

 upon the leaves of Beech quite early in the season. The presence of the 

 mite is shown by large irregular white masses on the under surface of the 

 leaves which have a glittering appearance resembling hoar frost. Under a 

 microscope, this appears as a mass of innumerable, minute, spherical gran- 

 ules. Among these are the mites, which are few and very difficult to locate. 

 The upper surface of the leaves upon which the frost mite is working are 

 discolored and in some cases distorted. Occurs on Beech {Fagxis sylvatica). 

 Very common. 



Eriophyes sp. This consists of a mass of minute, yellowish, transparent, 

 granular bodies upon the leaf, growing together in such numbers as to 

 form large patches of frost running between the ribs, which hide the leaf. 

 The patches vary from 1 cm. -3 cm. in length and from .25-lcm. in diameter. 

 Among these granules are the mites which are extremely minute, the small- 

 est of all the mites yet examined. Occurs on Paper Birch (Betula papyri- 

 fera). Common. 



Eriophyes vitis. These are typical Eriophyid galls about .5 cm. in 

 length by 2.5 m.m. at the widest portion to I m.m. at the constricted por- 

 tion near the leaf. The top of the gall is irregular, being much in appear- 

 ance like Eriophyes ahnorinis. The interior and the entrance to the gall is 

 lined with white vegetable hair. The galls are green in color and grow 

 mostly upon the under sides of the leaves, with the opening upon the upper 

 side. Occurs on Wild Grape (Vitis cordifolia). Not common. 



Eriophyes jraxini. The galls produced by this species of mite are found 

 upon several species of Ash, and vary somewhat in structure according to 

 the leaf upon which they are found, upon Red Ash being hairy, upon White 

 Ash glabrous, etc. They consist of somewhat irregular circular swellings 

 from 2-4 m.m. in diameter which protrude upon both sides of the leaf. 

 Sometimes they occur only 10 to a leaf, but sometimes as many as 75 are 

 found, entirely covering the surface of the leaf and so interfering with its 

 functions as to injure the tree upon which the galls occur. The surface of 

 the galls is rough. Several often unite, to form a large irregular patch. 

 On the under side are the minute, hairy-lined openings into the galls. The 

 galls are Eollow, thick-walled, and lined with numerous granular excres- 

 censes and irregular growths. The gall is of a lighter green than the rest of 

 the leaf. Occurs upon White Ash {Fraxinus americana) and Red Ash 

 {Fraxinus puhescens). Common. 



