V. V. TllKoliALl) 



:n 



p. iiioiislrosa, badly ali'ected. 



The only species not alVected here arc : 



P. j)oli(a, P. oiiion'ca, P. (tlnujiiiann and I*, (ildskiana. 



/ 



Fig. 8. 



B. Sitka Spruce completely defoliated b\ Aphis abietina Walker. A. First .stage of attack. 



Different effects produced on different varieties. 



Two very marked different effects are produced by this aphis. In 

 P. sitchensis the damaged needles soon fall and complete defoliation 

 results, as shown in the photos reproduced here. In P. excelsa the 



