I893-] 



GALL MITES 



251 



specimens. Would you care to have some galls of the 

 Phy tophi s ribis from black currant in their (I think) very 

 unusually advanced condition for this time of year ? If so, 

 I think I could procure some from Kent. 



It is with regret that I read in your letter that you are not 

 in strong health. But if you could work less severely might 

 not you hope to have benefit ? The excessively minute work 



i, Mite, greatly magnified natural length of female 0*23 millimetres ; 

 2, head and fore parts, still more magnified (by permission, after 

 Dr. A. Nalepa) ; 3, mite-galls of unusually large size, with one withered 

 and open. 



FIG. 65. CURRANT GALL MITE, PHYTOPTUS RIBIS, NALEPA. 



of your elaborate investigations must be exceedingly wear- 

 ing. In my own observations (which, indeed, are not to be 

 compared with yours) I always find they tell very much on 

 my health if I have at once to overwork my sight with the 

 microscope and my mind in the record of my observations. 



