lepidopterous larvce and pupa. 



171 



air-chamber at the top. The pupa rested upon wood, 

 but its surface was of course wet, and the air around it 

 was saturated with moisture. The pupa did not change 

 in coknir during the many hours it remained in the air- 

 chamber, but darkened, though more slowly than usual, 

 after being removed. The darkening in this species is 

 normally very rapid and complete, producing a black 

 roughened surface. Hence, if it be desired to examine 

 the surface of a pupa as it is immediately after throwing 

 off the larval skin, such an object could probably be 

 attained by placing the quiescent and contracted larva, 

 before pupation, in a chamber containing air saturated 

 with moisture. 



The following are the observations of loss of weight in 

 the pupfe of Smerintlius ocellatus made during the last 

 summer (1885). 



I. A pupa of Smcrinthus ocellatus which had changed for 

 some days, and of which the surface was thoroughly 

 hard and dark, was weighed upon the following 

 dates: — 



Hour. 



7.25 

 9.25 



11.25 

 9.25 



10.18 

 1.20 



10.47 

 6.40 

 4.30 

 2.50 



p.ui. 

 a.m. 

 p.m. 

 p.m. 

 a.m. 

 p.m. 

 a.m. 

 p.m. 

 p.m. 

 p.m. 



Day. 



Aug. 23, 1885 



24 „ .. 



24 „ .. 



25 „ .. 



27 „ .. 



28 „ .. 



29 „ .. 



30 „ .. 



31 „ .. 

 Sept. 3 „ .. 

 Feb. 24, 1886 



Weight. 



2-322 grams. 



2-320 „ 



2-318 „ 



2-314 „ 



2-308 „ 



2-305 „ 



2-302 „ 



2-298 „ 



2-295 „ 



2-291 „ 



2-064 „ 



The total loss in nearly 11 days (all but 4 hours 

 35 minutes) is 31 milligrams, on an average about 

 3 milligrams a day. But even here the loss is larger on 

 the earlier days. 



In the 25 weeks between Sept. 3rd 1885, and Feb. 24th, 

 1886, the pupa lost 227 milligrams, or 5 milligrams a 

 week. This is an immense loss as compared with that 

 shown in other pupne, and is certainly abnormal, and the 

 pupa on investigation was found to be dead. The compara- 

 tively rapid loss of weight in dead pupae has been shown 

 by Prof. Meldola (Ann. and Mag. Nat. Hist., Oct., 1873;. 



