THE TRIBE OF THE FRITILLARIES 129 



ovaries of the butterflies. These eggs hatch in about a 

 week and the caterpillars become full grown a month later. 

 They then change to chrysalids in which condition they re- 

 main another week, thus requiring five or six weeks for the 

 newly laid eggs to mature into butterflies. Supposing 

 the eggs were laid the first week in June, the butterflies of 

 this second brood would appear about the middle of July. 

 The eggs in the ovaries of some of these butterflies also re- 

 quire several weeks before they are ready to be laid, so that 

 it may be about the tenth of August when this happens. 

 These hatch and mature to chrysalids during the next six 

 weeks, the butterflies of this brood emerging about the 

 middle of September. These in turn lay eggs at once ap- 

 parently, no extended period being required for their de- 

 velopment before they are laid. The eggs hatch during the 

 latter part of September and the young caterpillars feed 

 upon the violet leaves for two or three weeks, moulting per- 

 haps twice and becoming approximately half grown. They 

 now stop feeding and go into a lethargic condition in which 

 they hibernate. Then in spring they awaken and feed 

 again upon the violet leaves for a short time, becoming 

 mature and changing to chrysalids sufficiently early to 

 emerge as butterflies late in May. 



In this hypothetical group we have a fairly normal con- 

 dition of a three-brooded butterfly hibernating in the stage 

 of the half -grown larva and requiring some weeks for the 

 development of the eggs in the ovaries of the butterflies in 

 the case of the first two broods but not of the third. 



In another group, which we may designate as B, the con- 

 ditions may be similar except that the butterflies lay their 

 eggs very soon after coming from the chrysalis in the case of 

 all three broods. Obviously there would be a tendency 



