GALL MITES, 361 



ivn in the woodcut. It is common in this 

 country on the plum tree. In Bohemia Drs. Amerling and 



CASE Its appearance is shown in the woodcut. It is common in this 



Twig of plum tree with galls of Volvulifex pruni. Leaf of plum tree with galls of VolvuHfex pmni. 



Kirchner thought that it only appeared there on those trees that 

 were growing old ; but there is no such restriction in this country. 

 It is already formed in the month of May, and afterwards becomes 

 harder 



PiiYTOPTUS SALicis. — 11. Leaves of sallow, tree bearing galls of ditto ; 

 12. Sketch of ditto ; 13. Magnified sketch of leaves with ditto ; 14. 

 Magnified section of gall ; 15. Magnified figure of insect. 



The insect in this case is exactly like those found in other galls 

 of this kind, but is not yellowish-white, but a distinct yellowish 

 orange colour, although still pale. The woodcut on page 337 

 represents the appearance of the leaves when attacked, and a 

 magnified section of the gall itself. This is one of the galls that 

 we have found swarming with the mites, and then there were no 

 hairs or cottony matter growing inside, although appearances of 

 its having grown. 



