ERIOPHYID^ OR GALL-MITES. 



35 



respective food-plants are distinct species, and tlierefore very fastidions 

 as to food. 



Mr Newstead, Curator of the Grosvenor Museum, Chester, carried 

 out a number of observations with regard to the species on black 

 currant, and found that there vi^as a succession of lu-oods from 

 February to September. He also discovered that when the buds 

 shrivel up and become unalile to support the mites, they migrate 

 to the leaves and leaf-stalks, and enter the newly formed buds 

 towards the end of July, where they remain until the following 

 spring. 



From preliminary observations I find that there is a slight difference 

 between the habits of the species on hazel, compared with tliat on 

 l)lack currant, inasmuch as the 

 " blind buds " of the former do 

 not shrivel up so quickly as the 

 latter. Consequently the swol- 

 len buds of hazel are teeming 

 with life about the latter end of 

 July, while comparatively few 

 are on the leaves and leaf-stalks. 

 The buds for the coming year 

 were then formed, and the mites 

 would be able to move from 

 one " house " to the other 

 without camping out during 

 nature's building operations. 



The life -history of those species living in galls is not so easily 

 followed. For instance, I have examined the buds and twigs of 

 a lime-tree, from the same branches which year after year produce 

 galls on the leaves, without finding a single mite. Then, again, 

 certain willow leaves are infested annually by a micro-fungus of 

 the rust order, on the under side of the leaves, which invariably 

 harbour those mites, and yet neither " leaf-galls " nor " blind buds" 

 could be found on the tree whither the mites would be supposed to 

 migrate from the fungus excrescence, whose existence as a rust only 

 lasts for a month or two. 



On the under side of the leaves of some lime-trees a white growth 

 is often found, which is known as a vegetable hypertrophy. This also 

 harbours mites, and yet no nail-galls may be seen on the leaves of 



Fig. S7.-^rkiUs 

 platanus) or, 



I Inifof sjicnmorc (Acer pseudo- 

 •il hy Pliyllocoptes acericola. 



