142 THE MONTANA EXPERIMENT STATION 



LIFE HISTORY AND DESCRIPTIONS 



THE EGGS 



The egg, when first laid, is white in color, but before hatching 

 it becomes brown. The eggs are attached to grass and other vegeta- 

 tion and hatch in a very few days after being laid. (Gillette, Bulletin 

 94, Colorado Experiment Station.) 



The eggs for the brood of caterpillars that proved so destructive 

 Vk'ere probably laid late in September. We cannot give exact infor- 

 mation on this point as we were unable to secure eggs from the stock 

 of moths we had. We do not know the duration of the egg stage. 



THE YOUNG WORMS 



The young cutworms are very small and are very dark colored. 

 Ihey secrete themselves in the stools of wheat and the close-by 

 earth but ^'o not avoid the light as noticeably as when larger. They 

 crawl with a looping motion, thus resembling the measuring worms. 



HIBERNATION 



The caterpillars do not hibernate at any particular size or age 

 but in general are about half grown when cold weather sets in and 

 causes them to become dormant and enter the period of hiberna- 

 tion. They hibernate from two to three inches under the surface, 

 though we were informel by farmers that great numbers of them 

 could be found just between the snow and soil. 



THE AWAKENING IN THE SPRING 



As the warm spring days come on the cutworms become active 

 but a cold storm, such as we often have in our climate at this season 

 of the year, causes them again to become quiescent for a time, only 

 to become active again with the return of higher temperaturt^. 

 Thus they begin to be active very early in the spring and b}^ the 

 time the vegetation has made an appreciable growth the cutworms 

 have increased in size. They eat ravenously at this season of the 

 year and grow very rapidly and, as green vegetation is more scarce 

 at this time, the effects of the presence of the cutworms become 

 very noticeable. Their presence is particularly noticeable if the 

 field has been ploughed in the spring and the vegetation on which 



