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58 THE CANADIAN ET OMOLOGIST. 



Mr. ScLidder, speaking of a white butterfly taken in Eastern Labrador,, 

 says that it is very closely allied to, but distinct from P. oleracea-. In a 

 note following the description of P. fj'igida, he adds : " It would be 

 " exceedingly difficult to distinguish this species except by immediate 

 " comparison with both sexes of oleracea ; the differences are more easily 

 " seen than described, although the extreme limits of variation oi oleracea 

 " do by no means permit us to include within its boundaries this com- 

 " paratively persistent form ; it is more heavily marked than any specimen 

 '^ of oleracea which I have seen.'' 



The Pieris which Mr. Grote has named Ganoris horealis is found along 

 two hundred miles of sea-coast on Anticosti ; it is quite abundant on the 

 north shore of the Gulf, terminating in a western direction in the neigh- 

 borhood of Seven Islands. It occurs throughout the north, on the 

 Labrador Islands, into the Straits of Belle Isle, and probably Newfound- 

 land. I am aware that P. oleracea occurs at Quebec, and it may extend 

 on both sides of the St. Lawrence opposite the mouth of the River 

 Saguenay ; but it is not found below the latter river, towards the Gulf. 

 It seems curious that Pieris frigida or Ga/ioris borealis should, like Papilio 

 brevicaiida, be confined to the north coast and islands of the Gulf of St. 

 Lawrence, and that the caterpillar of the Anticosti Pieris is difterently 

 marked and the habits of the butterfly contrary from that of oleracea. 

 What is the object of the study of eggs and larvee of insects ? Is it not 

 for the purpose of determining the value of species ? 



The object in claiming primitive source for some of the northern 

 butterflies, arises mainly from the fact that in them we discover perman- 

 ency in form and color, while their geographical range is limited in 

 accordance with the distribution of their food plants. That species found 

 scattered over defined circuits are generally tending towards the equator. 

 That many of these are but figurative races removed from their original 

 habitat, and have varied through the influence of food and climate. 



In this connection I quote an extract from Geographical Distribution 

 of some Genera of Insects, by Francis Walker, F. L. S., Vol. iv, No. to 

 of Can. Ent. : " In studying the fauna of a mountain it is most suitable 

 " to begin with the top, and to trace it downward, where the agencies or 

 " forms of life become successively more numerous and complicated in 

 " their mutual adaptations and limitations, all being as wheels which serve 

 '' to regulate the great living mechanism of which they are the parts. In 

 " like manner, in noticing the faunas of the two primary mountains into 



