Sept. 4. 1916 Life History of Army Cutworm 873 



moths had emerged recently in the vicinity, the experiment was 

 abandoned. 



On numerous occasions attempts have been made to find moths in 

 the field in the act of depositing eggs, either on crops or on vegetation 

 on virgin sod. Much time has also been spent in searching for eggs on 

 grasses, clover, alfalfa, stools of volunteer grain, and other cultivated 

 plants. A few eggs of other noctuids have been found, but none of this 

 species. 



CAGE EXPERIMENTS 



In April and May, 1915, there occurred in Montana a widespread and 

 very severe outbreak of the army cutworm. Moving armies of the 

 larvae were reported daily, and many thousands of acres of fall wheat 

 were eaten off during April and May, so that it was possible to obtain a 

 supply of the living insects for study. Plans were made for a twofold 

 effort in connection with the outbreak. It was decided to install several 

 large cages outdoors and by any means possible to obtain adult moths 

 of both sexes, place them in the cages, and attempt to feed and keep 

 them alive until they should lay eggs, correlating the observations made 

 in these cages with notes from the field. 



Three large cages 24 inches square by 40 inches high were installed on 

 the lawn near the insectary. These are of fine-mesh brass screening and 

 are fastened to the earth by a broad baseboard which is inserted in the 

 soil. A large door fills one side and in this door is a smaller one, suffi- 

 ciently large to permit the insertion of the hand. On the 24th of April 

 28 larvae were placed in cage 2 and 53 in cage 3. These worms had been 

 collected from two fields at Willow Creek, Mont. They were fed regu- 

 larly, but did not do well. It has been repeatedly found that it is diffi- 

 cult to rear a large proportion of these caterpillars when fed in a body in 

 one cage. For this reason in rearing record specimens the writer has 

 adopted the method of feeding the caterpillars individually in tin boxes 

 and by so doing has brought nearly every individual to maturity. 

 None of these caterpillars pupated in the large cages. 



On June 10 about 300 pupae which had been taken from the soil in 

 a field at Willow Creek were brought to Bozeman and placed in cages 

 1 and 2. Not one of these emerged. When examined, they were dead 

 and decayed. They had been placed individually in holes in the soil 

 with the anterior end uppermost — a method which has been used with 

 dry soil with much success in indoor rearing. It is possible that rains 

 had closed the holes and injured the pupae by puddling the earth around 

 them. On the 20th of June, 13 moths which had been reared in the insec- 

 tary were placed in cage 1, and on July 17 about 50 moths which were 

 captured out of doofs at Willow Creek were divided between cages 1 and 2. 

 It was hoped that some of these would grow ova and deposit eggs. Sponges 

 saturated with honey water were placed in the cages daily and clover 



