ERIOPHYID.E OR GALL-MITES. 



21 



easily recognised. In the former the buds are comparatively 

 small and pointed, whereas the latter are swollen and rounded. 

 A longitudinal section made in winter or spring through the centre 

 of both classes of buds will show a difference of structure. In the 

 case of the healthy buds as, for ex- 

 ample, in the currant-bud mite the 

 embryo leaves can be seen, and they 

 are always close at the apex, while in 

 the diseased buds the structural fold- 

 ings of the leaf are broken up, and 

 the apex always open. The same de- 

 scription holds good in forest trees in- 

 fested by Eriophyida3. 



The life - history and microscopical 

 characteristics of the genus Eriophyes 

 form a most interesting study. It 

 belongs to the sub-family Eriophyidae 

 (Phytoptida?), gall-mites of the order 

 Acarina. 



The mite is of a light yellowish 

 colour, and varies very much in size 

 according to species. Perhaps the size 

 of the creature may be approximately 

 put down as the ^i^ to y^Vo of an 

 inch in length, and it is obviously 

 indistinguishable by the naked eye. 

 Fig. 22 may be regarded as a typical 

 mite. 



The body is of a vermiform shape, 

 and, like mites in general, is of one 

 piece, and with few appendages. Hence 

 a creature of such simple structure 

 aifords but few points for specific differ- 

 ences ; nevertheless, K"alepa gives a full description of a typical 

 mite, together with a detailed description of the respective 

 species. 1 



The form of the body is an elongated ellipse, narrowing towards the 

 posterior end ; and the cephalo-thorax is about the same breadth as 

 1 Das Tierreich, 4 Lieferung (Eriophyidso). 1898. 



Fig. 22. Phytoptus calycophthinis, 

 Nal. (Eriophyes rudis, Canest.) 

 (Photographed from Nalepa's ' Gen- 

 era and Species derFamilie Phytop- 

 tida.' Wien, 1S91.) 



