Insects, etc.., Injurious to Nuts. 313 



When very abundant on the sweet chestnut the boxes should be 

 collected and burnt, if on young trees. 

 On old ones it does but little harm. 



REFERENCES. 



(1) Fishcr-SchlicJi. ' Manual of Forestry,' vol. V., p. 193 (1895). 



(2) Theobald, F. V. AnirnaLPests of Forest Trees. Journal S. E. Agri. Coll., 



Xo. 13, p. 185 (1904). 



III. TO WALXUT. 



THE DUSKY-VEINED WALNUT LOUSE. 

 ( Ptychodes juglandis. Frisch.) 



This is one of our most beautiful aphides, and it is strange that 

 such a conspicuous insect's life-history should remain still unknown. 

 It is well figured by Buckton (1). 

 I observed it for nine or ten 

 years regularly (2) working 

 upon some large walnut trees 

 at Kingston - on - Thames ; but, 

 although present in plenty, it 

 never increased sufficiently to 

 do any serious harm to the trees 

 until 1894, when this and other 

 pests were most destructive. 

 The earliest note of the creature's 

 appearance upon the walnut leaf 

 was the 1st of July ; in 1894 

 none were observed until the 

 10th of July. In all instances 

 the form of aphis first observed 

 upon the leaves was the winged 

 viviparous female. The follow- 

 ing is copied direct from my 

 notes : " These plant lice are 

 always to be found on the upper 

 surface of the walnut leaves, 

 and in two rows close to the mid 



rib (Fig. 212). The winged females usually settle and fix themselves, 

 before reproducing, in patches of fourteen to twenty, seven or ten 

 on each side of the mid rib ; with their heads invariably pointing 



[F. Edenden. 



FIG. 212. THE DUSKY- VEINED WALXUT LOUSK. 



Nymphs on leaf and just hatched adult on 

 left of nymphs. (Enlarged. ) 



