872 Journal of Agricultural Research vol. vi.no. 23 



of benefit to any who have occasion to search for the eggs of other Noc- 

 tuidae. On account of the irregular occurrence of the species, it has 

 been quite impossible to depend upon getting a supply of living speci- 

 mens for study when wanted, and a continuous effort in the search for 

 the facts desired has been out of the question. In the nature of the case, 

 instead of laying out and following a definite plan of study the successful 

 pursuit of which would certainly lead to the results desired, it has been 

 necessary to rely largely upon scattering observations made through 

 several years as opportunity was afforded. 



The first attempt to obtain the early stages was made in 1907, when, 

 in the writer's first experience with an outbreak of the species, a large 

 number of moths originating from larvae which had been brought in 

 during the fall, were reared during the winter in the insectary and were 

 held in large Riley-type cages in order that they might have an oppor- 

 tunity to lay eggs. All of the moths died within a few days, and no eggs 

 were laid. In the spring several hundred larvae were brought in from 

 grain fields and fed to maturity. The moths which emerged were left 

 in the cages and given water and a variety of plants upon which to lay 

 eggs. Again the moths died without laying eggs. 



Several explanations for the failure suggested themselves. It was 

 thought possible that the moths were not normal because of having 

 been reared in confinement. A number of female moths were dissected 

 for the purpose of examining the ovaries, and it was found that the ova 

 were immature. The idea suggested itself that the failure to develop 

 ova was the outworking of some little understood principle of periodicity 

 in the occurrence of the species, and it was also thought that the absence 

 of mature ova might be due simply to the lack of food after the emergence 

 of the adults. 



In the spring of 1910 there was a destructive colony of the larvae 8 

 miles west of Bozeman, and plans were laid to recover a supply of the 

 pupae from the soil, allow them to emerge in confinement, and attempt 

 to feed the adults on honey water to get them to grow ova. Our trip 

 to the field to secure pupae was not correctly timed, and the moths had 

 already emerged. Accordingly, an attempt was then made to obtain 

 moths by catching them at night near the same field. A special trap 

 light was arranged, consisting of a wooden box 18 inches square and 12 

 inches high with an 8-inch circular hole in the top into which was in- 

 serted a large funnel-shaped tin with a 2 -inch opening at the bottom. 

 Above the funnel was placed an acetylene light from a stereopticon. 

 This furnished a very strong light, and the night was favorable. The 

 writer and an assistant went to the field, expecting to spend the night. 

 They remained until between 12 and 1 o'clock, but only a few moths of 

 any kind came, and none of C. auxiliaris. As no encouragement what- 

 ever was received, even though it was known that many thousands of 



