146 Transactions. — Zoology. 



usually on the ninth and tenth days of life. Thus about 

 eighteen eggs were laid, and oviposition was continued for 

 five or six days. The eggs are small, white, iridescent, 

 crinkled ; and when the caterpillar emerges it does so by a 

 small, regular opening at one end. Before I clearly distin- 

 guished males and females two females were occasionally put 

 together. In this case nothing happened till about the eighth 

 day of adult life, when one or both of the moths laid all her 

 eggs (eighteen to twenty in number) in a few hours, and 

 shortly afterwards died. These unimpregnated eggs were 

 yellowish in colour, and never developed. The eggs are scat- 

 tered about the leaf on which they are laid ; the female has 

 great difficulty in extruding them, as they cling to the genital 

 aperture, and have to be rubbed off against the leaf. It fre- 

 quently takes over fifteen minutes to lay a single egg. 



The eggs hatched in from eight to ten days in a uniform 

 temperature of 60° Fahr. 



The appearance of the caterpillar is well known. In an 

 equable temperature and with an abundant food-supply its 

 active life lasted for twenty-two days ; by this time it is full- 

 fed, and spins its delicate white network cocoon. 



The time of pupation averaged seventeen days in a room 

 rather cooler than that used for hatching and feeding. 



Summary. 



Length of life of adult (average of thirty-five), ten to fifteen 

 days ; eggs laid (average of nine pairs), on third to seventh 

 day of life ; number of eggs (average of nine pairs), eighteen ; 

 eggs hatched (average of about forty), on the ninth day ; life 

 of caterpillar (average of nineteen), twenty-two days; pupa- 

 tion period (average of twenty five), seventeen days : dura- 

 tion of cycle, fifty-three days. 



The proportion of larva? that reached adult life was very 

 large — fully 80 per cent. Only one specimen of the common 

 parasitic Hymenoptera was obtained from thirty pupae, though 

 in England about 70 per cent, of the pupae have been found 

 to produce parasites. 



