312 THE CANADIAN ENTOMOLOGIST 



Male. — With the second moult the male enters a quiescent 

 period known as the propupal stage during which no food is taken, 

 and which is characterized externally by the begirining of a wax 

 secretion over the scale or puparium which becomes separate from 

 the insect. All larval appendages are cast off and are replaced 

 by the developing legs and wings of the adult. This period is 

 transitional, seldom extending more than two days. 



• 



The true pupa, which is flesh-coloured, may be easily seen 

 beneath the opaque puparium, being distinguished only by the 

 further development of its appendages and by the distinct seg- 

 mentation of the body. Externally the secretion of w3x has con- 

 tinued and the male scales differ from those of the females in their 

 smaller size, more elongate shape, and wire-glassy appearance. 



In from three to seven days the final moult of the male takes 

 place within the puparium and is indicated by the wings and de- 

 veloping caudal filaments which often protrude beyond the scale. 

 (Plate XV, fig. 6.) In a few hours after the last transformation 

 the mature insect backs out from the puparium and is ready for 

 flight. It is very delicate and lives but a few hours. 



•The emergence of the male generally covers a period of 

 four weeks, the date of earliest emergence depending largely on 

 the host species. The first males were bred out froni scales col- 

 , lected on linden. They issued from the middle of April till the 

 middle of May. On hickory and bittersweet males did not begin 

 to emerge until the first of May and continued to mature until the 

 middle of June. On elm and white ash they did not begin to issue 

 until late in May, and the last individuals appeared late in June. 



Female. — Following the second moult the female increases 

 rapidly in size. Owing to the continued growth the protective 

 wax covering is split and appears as irregular plates on the dorsum. 

 These finally disappear and when mature the female* is smooth, 

 broadly oval, and slightly convex, with darker markings plainly 

 visible on the lighter specimens. The comparative size with that 

 of the male is indicated on Plate XV, fig. 1. Several stiff iridescent 

 strands of wax project from the margin of the scale which may 

 function as a secondary sexual character. Shortly after impregna- 

 tion a chestnut or brown colour prevails, the surface becomes 



