298 THE CANADIAN ENTOMOLOGIST. 



vania series. Some from North Bay, however, have the furcula as short 

 as those from Lake Simcoe (figs. 56, 57, 58.) 



5. Cerci of ^. — Next to the furcula this structure shows the greatest 

 range of variation. It is much stouter in typical giacialis than in typical 

 variegata, and Scudder used the character as one of the chief ones by 

 which the two species could be distinguished. A glance at the plate, how- 

 ever, will suffice to show that no separation into two species can be based 

 on the form of this structure. Some of the North Bay specimens have the 

 cerci of typical giacialis, but there is a perfectly gradual series of transi- 

 tions from the stout cerci of the more northern forms to those of the 

 Pennsylvania ones, in which they are most slender. In order to illustrate 

 these transitions as accurately as possible, I have drawn the cerci of all 

 the $ specimens, from N. E., North Bay, Algonquin Park, Tobermory 

 and Pennsylvania, and a sufficient number from L. Simcoe to complete 

 the range of variation. 



Other variations of less importance are to be found, especially in the 

 general colour and character of markings, but they add nothing to the 

 facts gained from the above. 



From these comparisons it is readily seen that the specimens from 

 Mt. Washington and those from Pennsylvania are the most widely sepa- 

 rated, but that the wide gaps between them can be filled by a complete 

 series of links represented by the Canadian specimens, the most northern 

 of which closely approach the N. E. specimens, the most southern the 

 Pennsylvania ones. 



These variations, hence, appear to be connected with differences in the 

 climatic conditions, and it would seem that temperature is an important 

 factor. They are also accompanied by certain changes in the insect's 

 habits, as evinced by some interesting facts that have been recorded on 

 this subject. Mr. Scudder states that in the White Mts. P. giacialis " fre- 

 quents the close branches of the dwarf birch, and is rarely or never seen 

 upon the ground," while Mr. Morse found most of his specimens " on or 

 among the various species of Vaccinium, characteristic of mountain-tops 

 and on Ascutney upon dwarf cornel" (Psyche, 1898, 273). It occurs 

 at elevations of 2,000 to 5,400 feet, in New England, New York and 

 Pennsylvania, but has also been taken at lower levels at Jackman, Me., 

 on the Canadian border, " in open woods and bogs " (Harvey. — Psyche^ 

 1897, 77). At North Bay and Algonquin Park I found the insect 

 common in open woods on bushes, chiefly the common beaked hazel 



