CURRANT GALL MITE. 35 



At present (besides continuation of other experiments) observation 

 is being made as to presence or non-presence of tiie Phytnptl about the 

 base of the stems of the Currants or in the earth round them. In 

 this I am able to co-operate to some small extent, for during some- 

 what more than eleven years in which I have had the Black Currant 

 bushes in my garden here (at St. Albans) under my observation, I have 

 never found any presence at all of Mite Galls. Therefore it is fair to 

 suppose that if the quite cut-down bushes, with the remains of the 

 stumps and the adhering earth treated in various ways, which have 

 been transferred to my garden from Woburii for special observation, 

 should prove in the coming summer to be mfested, that in this case 

 the Gall Mites must have survived the treatment, and been conveyed 

 on the stumps or in the earth. 



Should (on the contrary) these cut- down and dressed plants con- 

 tinue free from infestation in the uninfested ground, and similarly 

 cut-down and dressed plants in the neighbourhood of infested bushes 

 at Woburn show the pest, it would point strongly to the Mites straying 

 about, and this being one way of the trouble spreading. 



For a long time it was said (and truly) that we did not know the 

 history of the Mite, but, thanks to the observations of Dr. Nalepa, of 

 Vienna, and Mr. Kobert Newstead, Curator of the Grosvenor Museum, 

 Chester, this has long ceased to be the case ; we know what the life- 

 history of the Mites is on the bushes throughout the whole of the year. 

 To what extent they may stray about on, or in, the ground at the 

 roots of the bushes we cannot at present tell, but the regular life- 

 history is as follows. 



This Phytoptus ribis, which is the cause of so much mischief, is a 

 Mite so small as to be invisible to the naked eye, and differing from 

 the greater part of the families of Acarina, or Mites (which are eight- 

 legged, except in their youngest condition, and more or less oval in 

 shape), in being cylindrical, somewhat tapering to the tail, and having 

 throughout the whole life foicr legs ; the two pairs being placed beneath 

 the body just behind the head or mouth parts (see greatly magnified 

 figure, p. 34). Consequently on the action of these Mites within the 

 forming buds (or close to them) as early as the beginning of June, 

 when the leaf-buds are little more than a line, or the twelfth part of 

 an inch, in length, the swollen growth is formed which we know only 

 too well. 



The history is as follows : Starting with the beginning of the year, 

 the Mites may be found in January in the infested buds in perfect 

 condition, and unaffected by even severe frost, beyond possibly making 

 them somewhat sluggish ; and in February egg-laying was found to 

 have commenced on the 20th of the month, and eggs to be found in 

 hundreds in company with the adult Mites. By March 6th there were 



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