No. 4.] GYPSY MOTH — APPENDIX. 417 



otlier cage8 escaped in some unknown way, and, as the 

 chance of tinding the eggs in such cages was very small, 

 further attempts along this line were abandoned. 



For the other line of investigation, common jelly tum- 

 blers, containing about two inches of earth, were used, the 

 tops of the jars being covered with pieces of muslin which 

 were held in place by rubber bands. A pair of beetles 

 were placed in each jar, with gypsy moth larvae for food 

 and with fresh leaves to serve as food for the larvw. At 

 first the jars were kept in the insectary, but when the 

 weather became excessively hot it was thought best to 

 place them out of doors, and a large box with a screen cover 

 was selected for the purpose. The jars were examined 

 daily, and when eggs were found in the earth the beetles 

 were changed to other jars, those formerly occupied not 

 being; disturbed until the ego's hatched, when the earth was 

 examined and the number of young larvae carefully noted. 

 Great care had to be exercised in not allowing the grubs 

 to remain together too long, as under these conditions they 

 soon develop cannibal tendencies, and readily devour each 

 other. 



During the extremely warm weather, about the middle 

 of July, many of the grubs which had heretofore seemed 

 healthy began rapidly to sicken and die. Thinking that 

 perhaps more natural conditions could be ol)tained, I 

 made a cage consisting of a box twenty-four inches long 

 and five inches square, the lower end being covered with a 

 wire screen. The box was sunk in the ground and nearly 

 covered with soil, the top being covered with muslin held 

 in place by an elastic band. Although great care was 

 taken to feed and watch the grubs, at the end of eight days 

 all had died. Later more young grubs were placed in the 

 cages, but the results were very unsatisfactory. On ac- 

 count of these discouraging results, careful attention was 

 given to the insects confined in the jars. Later in the sea- 

 son a number of eggs of O. frigidum and O. calidum were 

 thus obtained, and, upon hatching, the young larvae were 

 isolated. A part of these larvae remained healthy, and with 

 o;reat care I was able to rear a few throuah their successive 

 stao-es. 



