84 



PEAR. 



PHYTOPTID/E, commonly known as GALL MITES.— Pear Leaf- 

 blister Mites. Phtjtoptus pyri, Nalepa ; (/ Typhlodromus pyri, 

 Scheuten ; ? Phytoptus pyri, Pagenstecker) ; and other species. 





Phytoptus pyki, female, nat. length circa 0-2 mm. ; left leg of the first pair of 

 P. tristriatus, and (smaller figure) of P. tristriatus var. carinea, magnified 550 times, 

 all after Dr. Nalepa. Infested Pear leaf. 



During the past year the presence of Mite Galls, that is, of the 

 deformed growth caused by the minute cylindrical four-legged Mites, 

 scientifically known as Pliytopti, has been more than usually observable. 

 Almost as soon as growth was sufficiently advanced for their formation, 

 we had the red or green nail-like galls on the Maple and Sycamore 

 leaves, and the swelled and stunted leaf-buds, caused by the Mites, on 

 Nut bushes. The Black Currant bud -gall was a bad trouble ; and we 

 had besides the blister-like form which injures the substance of Pear 

 leaves, the infestation which raises a kind of wall of little funnel- 

 shaped knobs round the edge of Plum leaves, and the less observable 

 bud-gall of the common Yew. 



For many years, the life-history of the minute Mites, which give 



