394 



Annals Entomological Society of America [Vol. XIII, 



of A. pomi if they are brought into warm room temperatures 

 earher than 20 to 30 days before the outdoor hatching period. 

 Even though the eggs failed to hatch, their rate of shrivel was 

 most rapid in the dry air and air of low moisture content. 



Besides the incubator experiments, several series of moisture 

 experiments were conducted indoors and outdoors with the 

 eggs of A. avencB and A. pomi during 1919 and 1920. In each 

 of these series approximately 2000 eggs were collected and 

 divided into four groups (A, B, C and D) with 500 eggs in each. 

 These were placed under four different conditions; two lots 

 (A and B) were kept indoors (greenhouse or laboratory) in 



TABLE I. 



Incubator experiments showing the effect of variations in moisture on the hatch 

 of the eggs of A. avence and A. pomi, 1917 and 1920. Constant temperature 

 80° F. 1917 and 70-72° F, 1920. 



* Killed by fungi. 



a temperature of 60-75° F. Lot A was placed in a moist 

 chamber which registered 90 per cent moisture or better, while 

 lot B was exposed to the usual indoor moisture, which was 

 somewhere between 35 to 50 per cent. The other lots (G and 

 D) were placed outdoors; lot C- in a moist chamber which 

 registered 75 per cent moisture or better and lot D subjected to 

 the natural outdoor environment during the two seasons. 



' Table 2 shows the results of these experiments. In each 

 series the eggs in lots A and C, which were located in moist 

 chambers, showed a greater percentage of hatch than the eggs 

 in series B a,nd D, which were exposed to the normal indoor or 



