194 INSECT "PESTS OF FARM, GARDEN AND ORCHARD 



almost invisible openings. These caterpillars become full 



grown in about three weeks, just 

 about the time the grain is mature. 

 About harvest-time the second brood 

 of moths appears. These lay their 

 eggs during July, depositing them on 

 the ripe heads if the harvest be a little 

 delayed, but on the wheat in stack if 

 harvest is prompt. Usually the 

 caterpillars hatching from these eggs 

 become full grown and remain in the 

 grain over winter, but in warm sea- 

 sons, especially if warm in September 

 or when the pest is unusually abun- 

 dant, a third brood of moths appears 

 early in September. These lay another 

 batch of eggs about the middle of 

 September, depositing them upon the 

 open ends of grain in stack or mow, 

 which thus becomes more infested than 

 that in the centre. In grain stacked 

 outside, the caterpillars of this brood 

 become full grown slowly and remain 

 in the grain over winter, but if in 

 the barn they grow faster and a 

 fourth brood of moths appears about 

 the middle of October, the moths being 

 noticed in threshing. The insects con- 

 tinue to breed within doors all winter 

 as long as any grain remains, though 

 they become sluggish and cease feed- 

 ing during cold weather. The number 

 of broods is entirely dependent upon 

 the latitude and weather conditions; 

 in the South, where they can breed 



continuously, there being as many as eight in a year. 



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