Nov. s. I92I Pale Western Cutworm 293 



SEASONAL HISTORY AND HABITS 

 DURATION OF EGG-IvAYING PERIOD 



During the season of 19 19 the eggs were found to be well developed 

 in the ovaries when the female moth first emerged, and egg laying began 

 and was completed within a short time under insectary conditions. 

 The first eggs were obtained from reared moths on August 17, the aver- 

 age period between emergence and the beginning of egg laying being 

 four days. Moths collected in the field on August 26, which appeared 

 to have just emerged, laid numerous eggs the following day and con- 

 tinued to lay until September 9. 



In 1920 no records were available from reared moths, but a study of 

 moths in the field seemed to indicate that the eggs that season were 

 not fully developed when the moths first emerged. Thus out of 35 

 moths examined on August 24 only one had well-developed eggs in the 

 ovaries. On September i many moths were found with the ovaries 

 filled with well-developed eggs. These moths were mostly badly rubbed 

 specimens, indicating that they had probably emerged some little time 

 before. 



Our field observations show that the height of the egg-laying period 

 is during the last week in August and the first week in September. 

 Eggs in smaller numbers may be laid during the first three weeks in 

 August and as late as October i . 



WHERE EGGS ARE LAID 



The first eggs obtained were from moths confined in tin rearing cans. 

 When the soil in the cans was dry and light most of the eggs were placed 

 from X iiich to i inch below the surface and could be found only by careful 

 searching. When the soil was hard and lumpy eggs were scattered 

 about on the surface and could be easily seen. In the rearing cans the 

 eggs were not always laid in the soil. Many of them were placed on 

 the stems, leaves, and flowers of alfalfa, and frequently scattering eggs 

 were found on the sides of the cans or on the screen covers. Thus out 

 of 243 eggs found in one can, 180 were found in the soil, 62 were found 

 on the stems, leaves, and flowers of alfalfa, and i was found on the 

 side of the can. Some were laid singly and others were in clumps of 

 2, 3, or 4, and sometimes as many as 40. 



In outdoor cages, where a variety of soil conditions and various kinds 

 of vegetation were available, eggs were laid only in loose, dry dirt. 



Under field conditions the eggs are very difficult to find, and the only 

 ones we have ever found were secured by carefully examining the soil 

 at the exact spots where females were seen in the act of egg laying. 

 Eggs are found most frequently in loose, mellow dirt from X to >^ inch 

 below the surface. This is an important point, and will be discussed 

 later in connection v^^ith the habits of the moths and from the standpoint 

 of control methods. 



