292 Journal of Agricultural Research voi. xxn.No. 6 



and dandelion which were used as food, and the cans could be easily 

 cleaned by replacing the filter paper whenever it became soiled. 



Pupae were placed in moist, well-pulverized soil in individual glass 

 vials I inch in diameter and 4 inches deep. Each vial was filled to a 

 depth of 2 inches with well-firmed soil in which a round hole i inch 

 deep was punched to receive the pupa, which was placed in it with the 

 anterior end uppermost. A small twig was placed in each vial so that 

 the moth upon emerging could hang from it and allow the wings to expand. 

 The vials were closed by cheesecloth held in place by rubber bands. 

 The best results were obtained by keeping the pupae in uniformly moist 

 and mellow dirt. Extreme dryness or excessive moisture often resulted 

 in the death of the pupse. Uniform moisture conditions were more 

 easily obtained by allowing water to run slowly down the side of the 

 tube instead of flooding it over the surface of the soil. 



After the moths emerged they were placed in wire s,creen covered 

 tin cans 3.5 inches in diameter and 2.5 inches deep. An inch of moist 

 soil was kept in the bottom of the cans, and alfalfa or clover blossoms 

 were added each day for the moths to feed upon (PI. 30, A) and to 

 hide under. Cutworm moths of all kinds seem very contented in these 

 cans, and with Porosagrotis orthogonia no difficulty was encountered in 

 getting the females to mate and lay eggs. 



Eggs were placed on filter paper in pint Mason jars with the caps 

 lightly screwed down. A few drops of water were placed on the filter 

 paper from time to time to provide the proper amount of humidity. 



IN THE FIELD 



A very good opportunity to watch the development of this insect 

 under natural conditions was afforded in a heavily infested field at Wil- 

 sall, Mont., in 19 19. This field was first examined on May i and was 

 visited several times a month all summer. Many fields in other parts of 

 the State were also visited, but that at Wilsall was the only one where 

 Porosagrotis orthogonia was followed through all stages of its develop- 

 ment. During the summer of 1920 a temporary field station was estab- 

 lished at Willow Creek, Mont., in a district where thousands of acres of 

 wheat had been destroyed during May and June. Moths appeared in 

 large numbers during August and September and were under observa- 

 tion at all hours, both day and night. Special attention was given to 

 the egg-laying habits, and for this purpose two observation cages were 

 set up. The cages were 2 -foot cubes with screen wire sides and solid 

 metal tops. They were placed over sunflower plants, and the ground 

 inside the cages was covered with soft dirt, stubble, clods, baked earth, 

 and green plants, thus offering the moths nearly all the natural condi- 

 tions of the neighborhood. Experiments with trap lights were also 

 carried on at the Willow Creek field station. 



