ERIOPHYID^E OR GALL-MITES. 35 



respective food-plants are distinct species, and therefore very fastidious 

 as to food. 



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

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

 currant, and found that there was a succession of broods from 

 February to September. He also discovered that when the buds 

 shrivel up and become unable 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 that on 

 black 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 campilio- out during Fi : f -Galls on leaf of sycamore (Acer pseudo- 

 r platanus) caused by Phyllocoptes acencola. 



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 



