174 



Mr. Poulton's notes in 1885 iqion 



Fifth period of 12 hours (about), from 9.43 a.m., Aug. 27th, to 

 10.12 p.m., Aug. 27th, a loss of 1 milHgram. 



Sixth, seventh, and eighth periods of 12 hours (about), from 

 10.12 p.m., Aug. 27th, to 10.40 a.m., Aug. 29th, a loss of 11 milli- 

 grams. 



The falling off is here continuous until the end of the 

 fifth period, when it again quickens somewhat. As the 

 loss is chiefly due to evaporation, it is easy to understand 

 how greatly it must be affected by atmospheric conditions. 

 A small error is introduced by the varying weight of the 

 card-tray, which increases when the air is moist, and 

 indicates a difference of 5 milligrams between the 

 extremes of three recorded weighings. It is exceedingly 

 probable that this cause may have assisted in the 

 augmented loss of the latest periods of 12 hours. The 

 weight upon Sept. 3rd, 1885, was 2*667 grams (sub- 

 tracting the weight of the card-tray), and that upon 

 Feb. 21st, 1886, 2*6145 grams, so that there was a loss 

 of 52"5 milligrams in a period of 24| weeks, or rather 

 over 2 milligrams a week. This loss is probably 

 exceptional, because the pup£e were kept in the house 

 in earth which was very dry, and for a period of many 

 weeks they were in an average temperature of 55° Fahr. 

 without being moistened. 



III. A pupa of S. ucellatus had thrown off the larval 

 skin at some time between 3.1 p.m. and 6.55 p.m. 

 on August 25th, 1885 ; but it had darkened con- 

 siderably, except upon the wing-cases : — 



