1916 



ENTOMOLOGICAL SOCIETY. 



127 



Xo success attended the attempts to breed the specimens through on spruce 

 and hemlock at this time. In the open, winged migrants were found locating on 

 the Douglas fir, confirming the experimental results, but in no case was any 

 winged migrant found on a spruce or hemlock in the open. Within a very short 

 time of settling on the needle of the Douglas fir the winged migrant commences to 

 oviposit, about 100-150 eggs being laid. These hatch in 6 to 7 days, and the young, 

 which are elongate oval in shape, and almost black in colour, with only a trace of 

 wax present, settle on the needles of the Douglas fir. There they remain motion- 

 less, without any apparent increase in size, through the rest of the summer, fall and 

 winter of the year, until the following spring; when having moulted once, they 

 commence oviposition as stem mothers on the needles oi the Douglas fir, laying 

 from 30 to 40 eggs, which hatch in numbers about the end of May and the begin- 

 ning of June. 



This life cycle was traced out for Stanley Park by observations on marked 

 twigs of Douglas fir, through the summer, fall and winter of 1914-15. During 



Stem mother on the Douglas fir. 



the first half of May, 1915, this generation on the Douglas fir was observed to be 

 dimorphic, about 50 per cent, of the lice developing wings and migrating back on 

 to the Sitka spruce, while the rest remained like the parent on the fir. 



The migration back to the Sitka spruce began about June 6. Experiments 

 were started in this case as well as in the case of the former migration to the fir, to 

 endeavour to determine for certain that the Sitka spruce was the return host. 

 Young trees, of the three coniferous species, spruce, Douglas fir, and hemlock, were 

 used, being enclosed in a cheesecloth cage. The fir was heavily infested with the 

 Cliermes and gave promise of good results. The numbers of migrants located was 

 disappointing, but gave clear indications that the Sitka spruce was the chosen tree, 

 the migrants found settling on the Sitka spruce in the cages were compared with 

 winged migrants found settling on the spruce in the open and proved identical. 



This form on the fir is Professor Gillette's Chermes cooleyi var. coweni. The 

 apterous forms left behind on the needles of the fir, increase in size, and amount 

 of wax secreted; lay a small number (30-40) of eggs, and the young on hatching 

 take up their location on the needles of the spruce, there to remain until the follow- 

 ing spring when they become stem mothers. The winged migrant to the spruce 

 lays 30-40 eggs, and then dies, the eggs hatch in about a week and the young, which 



