148 BUTTERFLIES 



brood a year and the butterflies belong to what I have 

 been calling the spring form. The butterflies appear on 

 the wing in early summer, lay their eggs upon the aster 

 leaves, and die. The eggs hatch into caterpillars that 

 feed for several weeks, then become dormant and remain 

 in such shelters as they can find until the following spring. 

 They then change to chrysalids to emerge as butterflies a 

 little later. There is thus but one brood a year and the 

 only form of the butterfly is the small, darker colored 

 variety. 



As far south as southern Canada there is a slight varia- 

 tion in this yearly cycle. The spring form of the butter- 

 flies appears in May and lays eggs. The eggs hatch into 

 caterpillars ; part of these caterpillars mature within a few 

 weeks, change to chrysalids, and come out in July or 

 August as the larger summer form of the butterfly, which 

 in turn lays eggs for the caterpillars that are to winter 

 over in a dormant condition and mature the following sea- 

 son. But the significant fact is that not all of the cater- 

 pillars which thus have hatched in spring go through this 

 cycle. Part of them become dormant when partially 

 grown and continue dormant through summer, autumn, and 

 winter, just as they did in Labrador. Then in spring they 

 develop into the spring form of the butterfly, along with 

 the caterpillars that have hatched from the eggs laid in 

 summer. There is thus what is called an overlapping of 

 the broods. 



Farther south, in southern New England, the life-his- 

 tory is more definitely two-brooded each year, as already 

 described in an earlier paragraph. Still farther south, in 

 the region of the Virginias, it is definitely three-brooded, 

 there being at least two summer broods during the year. 



