316 Insect Pests. 



winged females, which on examination proved to be this walnut 

 louse, upon privet leaves in a hedge surrounding the area where one 

 of the affected walnut trees grew. They remained feeding upon the 

 privet leaves until the 1st of October, when one and all died without 

 producing any oviparous generation.. 



Such, briefly, are the facts concerning this walnut pest as far as 

 we know. "Whether any wingless viviparous female does exist, and 

 where the winter quarters and where the early life (for it does not as 

 a rule appear on the walnut until the beginning of July or the end 

 of June) of this species are spent we at present do not know. I 

 believe from occasional observations, however, that fuller investi- 

 gations will show that P.juglandis spends its time, before the walnuts 

 are in proper leaf, upon the privet, and returns to that plant again 

 in the autumn, just as the hop louse migrates from the sloe and 

 plum to the hop in the early summer, and back to those prunes in 

 the autumn. 



I have found this aphis in plenty on walnuts at Wye, but 

 not sufficient to do any damage, also at Taplow, Cambridge, Worcester, 

 and in some places in S. Devon. 



Eemedial Measures. 



As to checking the increase of this pest, little can be done upon 

 trees when they are large. The lower branches and the small trees 

 were sprayed as high as possible, some with creolin, soft soap and 

 water, others with quassia, soft soap and water, both washes being 

 equally successful, as far as the destruction of the aphides went; 

 but there were constant migrations downwards from the high boughs, 

 so that it was almost impossible to check them. 



RErBRBNCES. 



(1) BucMon, Q. B. ' Monograph of British Aphides,' vol. III., p. 40 (1880). 



(2) Theobald, F. V. Notes upon Insect Pests in 1894, with especial reference 



to Insects attacking the Walnut, p. 15 (1895). 



THE COMMON WALNUT LOUSE. 



(Pterocallis juglandicola. Kalt.) 



This species is nearly always found on walnut trees, and can be 

 readily distinguished from the Dusky-veined Aphis by its abode 

 being on the under surface of the leaf and by its clear wings. It turns 



