( Ix ) 



Mr. F. Merrifield read a paper entitled " Systematic terape- 

 rature experiments on some Lepidoptera in all their stages," 

 and exhibited a number of specimens in illustration of his 

 paper. He commenced by describing some experiments on 

 eggs of Selenia illunaria and illustraria. These began to suffer 

 after about four weeks' exposure to a temperature of 33°, and 

 none survived it sixty days ; nearly all of those which died 

 matured after removal from the ice sufficiently to form the 

 larva within the egg-shell, but they were unable to break 

 through. Next, experiments on growing larva of illustraria 

 were described. All died within three weeks of exposure to 

 a similar temperature ; but some lived sixty-three days at a 

 temperature of about 47°, feeding slowly, and some of them 

 finally pupating ; the older larvffi seemed to withstand the 

 cold best. Larvae of E. autumnaria and E. alninaria were 

 much injured by the high temperature of 90° to 100°. 

 Experiments were tried on pupating larvae and pup^e. Pre- 

 liminary trials showed that larvae of the summer-pupating 

 brood of illustraria would pupate at 33°, occupying five or six 

 weeks in making the change, instead of two or three days, 

 without being injured by the process. Larvae of autimmaria 

 and alniaria would pupate at 47° or lower, and that tempera- 

 ture did not appear to injure the soft, green pupa of either 

 species, unless continued for very many days. Illustraria 

 pupje seemed injured by cold when the last day or two's 

 changes before being ready to emerge were proceeding, but 

 not when these changes were over, and the moths were only 

 awaiting the proper time of day when they would emerge 

 uncrippled at a temperature of 47°. A brood of autumnaria 

 larva from a single pair was divided ; some were forced (80°) 

 as larvae and as pupae, others forced as larva cooled (47°) as 

 pupae ; others were fed at the ordinary temperature (averaging 

 65°) as larva, and of their pupa some were left at that 

 temperature, others forced, and the rest cooled or iced. All 

 the pupa at 33°, 47°, or 65° produced moths that were dark, 

 and much spotted ; all the forced pupa produced moths pale, 

 and practically spotless; it seemed to follow that the dark 

 "British" autumnaria was not a dark race, but consisted of 

 individuals of which the pupa had been exposed to a tempe- 



