It appeared, therefore, that the only effect produced by cold in all chrysalides exposed more than three days after pupation was to retard the emergence of the butterfly. But even in some of these earliest exposed, and kept on the ice for full nineteen days, the only effect seemed to be to retard the butterfly. EXP. 3.--In June, 1879, eggs of the form _Marcellus_ were obtained, and in due time gave 104 chrysalides. Of these one-third were placed in the ice-box at from twelve to twenty-four hours after pupation, and were divided into 3 lots. 1st, 9 pupæ, kept on ice 14 days. 2nd, 12 ” ” 20 days. 3rd, 11 ” ” 25 days. Temperature 0°-1° R. most of the time, but varying somewhat as the ice melted. (Both in 1878 and 1879 Mr. Edwards watched the box himself, and endeavoured to keep a low temperature.) Of the 69 chrysalides not exposed to cold, 34 gave butterflies at from eleven to fourteen days after pupation, and 1 additional male emerged 11th August, or twenty-two days at least past the regular period of the species. Of the iced chrysalides, from lot No. 1 emerged 4 females at eight days and a half to nine days and a half after removal from the ice, and 5 are now alive (Nov. 18) and will go over the winter. From lot No. 2 emerged 1 male and 5 females at eight to nine days; another male came out at forty days; and 5 will hibernate. From lot No. 3 emerged 4 females at nine to twelve days; another male came out at fifty-four days; and 6 were found to be dead. In this experiment the author wished to see as exactly as possible--First, in what points changes would occur. Second, if there would be any change in the shape of the wings, as well as in markings or coloration--that is, whether the shape might remain as that of _Marcellus_, while the markings might be of _Telamonides_ or _Walshii_; a summer form with winter markings. Third, to ascertain more closely than had yet been done what length of exposure was required to bring about a decided change, and what would be the effect of prolonging this period. After the experiments with _Phyciodes Tharos_, which had resulted in a suffusion of colour, the author hoped that some similar cases might be seen in _Ajax_. The decided changes in 1878 had been produced by eleven and sixteen days’ cold. In 1877, an exposure of two days and three-quarters to eight days had failed to produce an effect. From these chrysalides 11 perfect butterflies were obtained, 1 male and 10 females. Some emerged crippled, and these were rejected, as it was not possible to make out the markings satisfactorily. From lot No. 1, fourteen days, came:-- 1 female between _Marcellus_ and _Telamonides_. 2 females, _Marcellus_.