THE CANADIAN ENTOMOLOGIST. 91 



In caterpillars that exhibit different shades of green, their external 

 appearances are due to the characteristic colors of their blood. If this 

 blood undergoes changes, the muscles, tissues and other parts, which are 

 the out-growths thereof, must evidently adapt their constitution and color 

 thereto. 



To my mind this theory seems perfectly plausible. Whatever cause 

 may be assigned to account for the phenomena, there is no getting over 

 the fact that the two are synchronous events. 



A DISSERTATION ON NORTHERN BUTTERFLIES. 



(Continued from Page £9). 

 BY WILLIAM COUPER, MONTREAL. 



The meeting with Papilio turmis on the Island of Anticosti, astonished' 

 me, as I did not expect to find this butterfly so far north in the Gulf ot 

 St. Lawrence. Only two specimens were taken during the season, and 

 old settlers say that it is always rare. Anticosti is evidently its most 

 northerly limit, as it does not occur on the opposite shore of Labrador. 

 It is common at Halifax, N. S., and in many localities along the south 

 side of the St. Lawrence, until we reach the lake and rocky regions on 

 the heighth of land from which the Assomption river flows north of 

 IMontreal. Plants of the family Oleaccce are generally selected by tnr7ius 

 as food of the larvae. They feed on Fraxinus trifoliaia and probably 

 the Swamp Ash of the south. The Anticosti food plant of turiius is not 

 known to me : it may be a species of Fraxinus ; whichever it is, the 

 Island of Anticosti, which stands between latitudes 49° and 50°, is 

 evidently the most northern range of that class of plants tending to the 

 existence of this butterfly.'^ 



* Note.— Mr. Scudder gives the following food plants of P. timius : Apule, 

 wild-thorn, choke ckerry, cultivated cherry, alder, tulip, bass-wood, oak, black ash 

 and birch. The former eight do not grow on Anticosti, but the latter two may 

 Mr. Saunders found them feeding on cherry — " Can. Ent., vol, i, p. 74." 



