CURRANT GALL MITE. 



303 



belong to the order of Acarina, or Mites. The subfamily of 

 the Fhytoptidcc are distinguishable l)y their peculiar long, 

 somewhat cylindrical, shape, and by having only two pairs of 

 legs placed close together beneath the fore part of the body, 

 which ends in a kind of conical projection containing the 

 mouth-parts. The details of those of the Black Currant Gall 

 Mite have not been described (as far as I am aware), but those of 

 the Pear-leaf Gall Mite consist of excessively fine sword-shaped 

 jaws fitting on each other like scissor-blades,* these being con- 

 tained, with other minute apparatus, in the somewhat conical 

 proboscis. 



Plujtoptus (species?) : infested buds; Gall Mite enormously magnified. t 



The skin is much wrinkled across, and the mite, besides its 

 two pairs of legs, is furnished with various large bristles, re- 

 garding the nature of which there has been much discussion. 

 The creature being excessively minute (so that the smallest 

 dot visible to the naked eye would be too large to convey an 

 idea of the size), there is great difficulty in saying with any 

 certainty whether various attacks to various plants are caused 

 by one or various species of the mites. 



Where I have traced the life-history the mites hatched (in 

 the same shape and with the same number of legs with which 

 they continued through their lives) from an egg (see p. 212), 

 which was of a perfect egg-shape at first, but which became, 

 towards hatching, very irregular in form, being pushed out by 

 the pressure of the mite inside, which I saw in the act of 

 coming out. As the mites grow they cast their skins, and 

 these empty cast-skins may be found among the living 

 multitudes. 



The injury to Black Currants consists in the mites, which 



* For further details of the Pear Gall Mite, see ' Der Milbensucht der Birn- 

 baume,' von Paul Sorauer. 



t For figures of seven kinds of Phytoptns attack, by Editor, including that 

 on Black Currant, see ' Economic Entomology: Aptera,' by A. Murray, article 

 " Gall Mites," pp. 355 — 301. 



