THE CANADIAN ENTOMOLOGIST. 225 



The butterflies confined on the plants at the Bloomfield bog were 

 examined on the 25th. They were all dead, and not a trace of an egg 

 could be found on the white mint or the golden-rod, but when I looked 

 over the cinquefoil 1 was rewarded by finding fifty-four eggs. It now 

 seemed certain that ihefruticosa was the right food-plant, and I became 

 convinced of it when I found nine more eggs by searching on the growing 

 plant. When I returned home ten additional eggs were discovered on 

 some cinquefoil which had been gathered in the bog. 



I now found no trouble to get eggs abundantly, both from females 

 confined in the open and" at home. In the latter case conditions 

 were always made as attractive as possible for the butterflies; fresh flowers 

 and leaves, with the stems kept in water, were provided in a large, light, 

 airy box. In this way, from fourteen females confined at the same time I 

 obtained two hundred and fifty-one eggs, an average of eighteen to each 

 female, lacking one. A single butterfly confined alone in the same way, 

 but in a large glass jar, laid twenty-four eggs, which, with seven eggs 

 dissected from the abdomen after her death, gave a total of thirty-one 

 eggs, the largest number obtained from any single female. From ten 

 females confined in the open I secured one hundred and sixteen eggs, an 

 average of eleven and one-half eggs, with one egg over. Of course some 

 eggs were undoubtedly deposited before the butterflies had been taken, so 

 that I am inclined to think that the average number laid by a single female 

 is not far from thirty. 



I quote from Dr. Fletcher's letter of Aug. 6, 1908 : 



" I don't know which I am shouting loudest, thanks to you for sending 

 me the precious eggs of dorcas or congratulations for having found the 

 food-plant. I must say I am surprised at this. As a piece of collateral 

 evidence that you are right in the food-plant, Dr. Brodie reported, you 

 remember, that he found the larvae on Hypericum perforatum, or rather 

 perhaps a plant which I may have understood him to mean for Hypericum 

 perforatum. Now, there is a sufficient resemblance between that plant 

 and Potentillafruticosa, when described superficially, for his plant to have 

 been that species, and where he found his eggs there is little doubt that 

 the Potentilla grows. I am very much surprised that it should have been 

 a Potentilla, but from your finding the eggs on the plant in the open, there 



is little doubt that you are right I think it just possible that 



these eggs will not hatch until spring. This is the case with thoe, 



sometimes at any rate It will be well for you to leave some 



of the eggs on the plants out of doors, where they were laid, and watch 



