128 



THE EEPOET OF THE 



No. 36 



were kept under observation until the winter, remain on the needles, and probably, 

 although this fact has not yet been actually followed in the case of Stanley Park, 

 remain stationary until the following spring, when they become stem mothers for 

 the new broods on the Sitka spruce. 



Full descriptions of the various forms of this species and its variety coweni 

 have already been published by Professor Gillette in the paper already cited; the 

 writer would like to take this opportunity of acknowledging the assistance rendered 

 by Professor Gillette in the identification of the material submitted to him. 



A careful study has been made of the various forms, using Professor Gillette's 

 published descriptions, and these have agreed in every case. 



Mention may be made here of the principal differences between the various 

 corresponding stages of the two forms on the fir and the spruce. 



Chermes cooleyi Gillette. 



Winged Migrant to Douglas Fir. 

 Antennal joints slender. 

 Antennal sensoria larger. 

 Pores of wax glands small. 



Stem Mother on Spruce. 



Wax glands large, with small pores. 

 Beak long and slender. 



Chermes cooleyi var. coweni Gillette. 



Winged Migrant to Sitka Spruce. 

 Antennal joints robust. 

 Antennal sensoria smaller. 

 Pores of wax glands large. 



Stem Mother on Douglas Fir. 



Wax glands small, with large pores. 

 Beak short and stout. 



Winged migrant to spruce; details of wax glands. 



Damage to the Spruce. The damage done to the Sitka spruce in Stanley 

 Park by this form] has been very considerable, a large number of trees have been 

 killed, whilst many others are in a dying condition and beyond hope of recovery. 

 Tlie fact that in most cases the whole of the young twig is destroyed makes the 

 injury very much more serious. 



The Do<jglas Fir. The damage done by the form coweni on the Douglas fir 

 has never been particularly noticeable, no deleterious effect on the health of the 

 fir in the Park having been noticed. Only in one case outside Stanley Park, in a 

 garden where a Douglas fir and Sitka spruce were growing alongside each other, 

 the spruce being very heavily galled, did the needles of the fir show effects of heavy 

 infestation later on in the summer. The nature of the damage on the fir is to 

 cause the needles to curl and bend at the points of attack. 



