A. Placed in the hothouse (12°-25° R.), immediately after pupation and left there till October 20th. Of about 40 pupæ only 4 emerged, 3 of which were _Prorsa_ and 1 _Porima_. The remaining pupæ hibernated and all changed into _Levana_ the following spring. B. Kept in a room heated to 6°-15° R. from November. Not a single specimen emerged the same year. This lot of pupæ were added to C from November. C. Placed on ice for a month immediately after pupation; then, from September 28th to October 19th in the hothouse, where no more butterflies emerged. The pupæ hibernated, together with those from lot B, in a room heated by water to 6°-15° R., and gave:-- On the 6th of February, 1 female _Levana_. ” 22nd ” 1 male _Levana_. ” 23rd ” 1 male _Levana_. ” 24th ” 1 female _Levana_. ” 25th ” 1 male and 1 female _Levana_. ” 28th ” 1 male and 1 female _Levana_. ” 1st of March, 1 male _Levana_. ” 13th ” 1 female _Levana_. ” 15th ” 1 female _Levana_. ” 19th ” 1 male _Levana_. ” 2nd of April, 2 male and 1 female _Levana_. ” 7th ” 1 female _Levana_. ” 21st ” 1 female _Levana_. ” 2nd of May, 1 female _Levana_. -- Total 18 _Levana_, 10 of which were females. The exact record of the time of emergence is interesting, because it is thereby rendered apparent that different individuals respond more in different degrees to a higher than to the ordinary temperature. Whilst with many an acceleration of development of 1-2 months occurred, others emerged in April and May, i.e. at the time of their appearance in the natural state. 11. Reared the second generation from eggs of the first generation. Emerged from the eggs on June 6th, 1872, pupated on July 9th. The pupæ were placed on ice (0°-1° R.) from July 11th till September 11th, and then transferred to a hothouse, where all emerged:-- On the 19th of September, 3 male _Prorsa_, 1 male _Porima_. ” 21st ” 13 _Porima_ (12 males, 1 female), 2 female _Levana_. ” 22nd ” 14 _Porima_ (12 males, 2 females) and 1 female _Levana_. ” 23rd ” 10 female _Levana_, 3 male _Porima_. ” 24th ” 5 female _Levana_. ” 25th ” 1 female _Levana_. ” 27th ” 3 female _Levana_. ” 4th of October, 1 male _Porima_. -- Total 57 butterflies (32 males and 25 females), only 3 of which were _Prorsa_, 32 _Porima_, and 22 _Levana_.