Nov. s, 1921 



Pale Western Cutworm 



301 



looked as though they had just emerged. One week later the number 

 of moths was greatly reduced ; the)'' were difficult to find during the day, 

 and very few came to lights at night. On September 30 an entire day 

 was spent in searching the same field, but not a moth could be found. 

 The ovvTuer of the field had been disking and drilling throughout the 

 month of September and during the first half of the month had frequently 

 seen moths fly up as the ground was disturbed but had seen none after 

 September 15. 



Seventy-five larvae collected in this field May i and reared in the 

 insectary at Bozeman emerged as adults on the dates shown in Table IV. 

 In 1920 at Willow Creek the first moth was caught on August 9, the 

 heaviest flight was from August 19 to 24, and several moths were seen as 

 late as October 8. 



Table IV. — Dates of emergence of Porosagrofis orthogonia moths in igiQ 



July 31. 

 Aug. 4 



5 

 6 



7 

 8 



9 



10 

 12 

 13 

 14 

 IS 

 16 



Number 

 of moths. 



Aug. 17 



18 

 19 



20 



22 



23 

 24 



25 

 26 

 27 

 28 

 31 



Sept. I. 



Number 

 of moths. 



4 



13 



3 



2 



5 

 S 

 4 

 4 

 2 

 I 

 I 

 I 

 2 



EGG-LAYING HABITS 



Egg laying was first witnessed at Willow Creek in 1920. Several 

 gravid females were placed in outdoor observation cages in which a 

 variety of soil conditions and vegetation was offered and were closely 

 watched for several days. On the afternoon of September 4, at 4.45, 

 one of these females was seen laying eggs. She crawled over clods, 

 stubble, and plants, constantly feeling with the ovipositor the objects 

 which she walked upon. On reaching a patch of soft earth she stopped 

 and carefully worked the abdomen into the soil until the wings were flat 

 on the ground. After remaining quiet for a short time she moved and 

 repeated her actions in another spot. Three ovipositions were made in 

 15 minutes, and after each one the dirt was stirred as the abdomen was 

 withdra-'vn and the hole left covered with dirt. The dirt around these 

 holes was carefully removed with a teaspoon and eggs were found in 

 clusters of 3 or 4 about % inch below the surface of the ground. A total 

 of II eggs were recovered from the three ovipositions. 



