14 MASS. EXPERIMENT STATION BULLETIN 261 



near the mininiuni effective temperature for egg production. With alternat- 

 ing temperatures above 17°, the rate of oviposition was in proportion to the 

 number of hours at the highest temperatures, the highest yields occurring in 

 the 32° combinations with low humidity. 



Experiments with Etjgs. 



Constant Environments. The results of incubating the eggs at 37° are given 

 in Table III (37°). Three different humidity environments were used, but 

 the eggs failed to hatch regardless of the moisture present, showing that a 

 constant temperature of 37° is unsuitable for incubation of the eggs. The 

 embryos not only failed to develop at this temperature but were killed, as 

 later exposure to lower temperature conditions did not produce any develop- 

 ment. 



The incubation of the eggs at 32° gave results similar to those at 37° (Table 

 III, 32°). Development failed to take place regardless of the humidity of 

 the environment, showing that the failure to hatch was again due to the high 

 temperature. An alternation of the eggs between wet and dry conditions did 

 not change the results. 



Table III.— The Effects of Moisture on the Eggs of the 

 Mexican Bean Beetle. 



Temperature 17° C. — Moisture Constant 



50 484 213 U.O 12.4 



