( xcvi ) 



80° F. (27° C.) it emerges with great regularity in about 8 

 or 10 days ; but the winter phase behaves very differently. Of 

 16 forced at 80° F. (27° C.) on the 26th November, 1890, and 

 11 more forced 14th December, all were dead by 1st February ; 

 of 16 kept at the more moderate temperature of 60° F. (16° C.) 

 on 26th November all were dead by 16th March ; many were 

 iced 26th November to 24th December ; of 8 of these forced 

 24th December and 7th January at 80° F. (27° C.) 6 died and 

 2 emerged, one a cripple ; while of those not forced until the 

 21st January or later, nearly all emerged and with fair 

 regularity. 



Tolerance of cold by summer pupa:. 



In contrast with winter pupse killed by the absence of cold, 

 reference may be made to the much greater tolerance of an 

 unaccustomed temperature shown by the summer pupa of S. 

 letralunaria and of A. levana, which I have kept, retarded and 

 changed in facies but uninjured by a low temperature, for 

 more than four months, that of Z. punctaria for more than 

 six months. 



Three or more broods. 



The resemblance of the summer phase to the continuously 

 brooded is perhaps also indicated by its readiness to repeat 

 itself by interpolating one or more broods between its 

 first and latest broods, which is so commonly the case 

 in a hot season, all but the last of them showing the 

 characteristic quality of the larva; of the summer phase, 

 i. e. the feeding up fast. The entomological periodicals con- 

 tain frequent instances of this. A. levana in a hot summer 

 often produces a third brood, and S. bilunaria (illunaria) from 

 eggs of the spring brood this year, has given me four 

 subsequent complete generations all of the summer phase, 

 having been kept by me at 70°-80° (21° -27° C.) during 

 their whole lives, the time occupied by them from the layiDg 

 of the first egg to the emergence of the last imago having 

 been only about six months, i. e. from 31st March to 

 2nd October. Thus, moths of five generations succeeded each 



