c.vjx'riniciit.s on funitr I jc phi opt era. 135 



(ii) Icimi larvce about to jjupate (Table IV.). — Eight 

 which were within a few hours of pupating were iced, 

 and all pupated in from 1 to 6 days, except 1 that died ; 

 they were kept in ice 28 days, after which 7 emerged as 

 perfect moths. 



(iii) Cooliufi and icing pupce in an advanced stage 

 (Table V.). — Eighteen were taken at from 7 to 11 days 

 after spinning up, cooled for 2 days, and then iced. Six 

 of them which were iced 28 days seemed quite unin- 

 jured, and all but 1 emerged. The other 12 were iced 

 60 days ; nearly all of these failed to emerge or were 

 cripples, 2 of them perhaps necessarily so from want of 

 space to expand their wings. 



Several pupae from sleeved larvae which \veYejnst on 

 the point of emerging, but which I wished to keej) back, 

 were cooled, and emerged in perfect condition. 



(2) Experiments with pupating larvce and jinpce of E. 

 avtumnaria and E. alniaria. — The next experiments 

 were tried with these species, which, so far as I know, are 

 never in the natural state subjected to a lower tempera- 

 ture than that of an English summer, averaging about 

 64°. The experiments were more than preliminary, 

 because they were also directed to ascertain the effect on 

 colour, and therefore will be again referred to under 

 another head, but are here referred to for the sake of 

 indicating their effect on the vitality and healthfulness 

 of those insects in different periods of the pupating and 

 pupal stMges. The details will be found in Tables VII., 

 VIII., X., XL, XII., and XV., in the appendix, and the 

 general results may be stated as follows : — Not the least 

 injury seemed to arise from exposing the maturf^d and 

 hardened pupa, the soft green pupa, or the pupating 

 larva to a cooling temperature ; and one pupa of 

 autnmnaria, exposed to a temperature of 33° within 15 

 hours after pupating, emerged as a moth in good condi- 

 tion. In the case of alniaria, 1 that was kept 42 dnjs 

 at 33'^ came out in good condition, as did 2 that were a 

 little older when iced, and were kept there 50 days. An 

 exposure to 33° for 58 days or upwards j^roved generally 

 fatal, and always more or less injurious, to autnmnaria, 

 but I am inclined to think alniaria would bear a much 

 longer exposure. An exposure of autumnaria for 28 

 days to a cooling temperature — which must be a much 

 lower one than this pupa is subjected to in its natural 



