J. W. H. Harrison 43 



respective losses of the "alcoholists." The natural deaths amongst the 

 untreated examples retained to act as controls were absolutely zero. 

 However, as will be seen, one death is noted ; this single death, as well 

 as one of those marked with an asterisk in the other column, was due 

 to the accidental crushing of the larvae by the twigs of the food plant. 



One must be careful to explain that the two groups were not differ- 

 entiated by the death rate alonfe ; such a supposition does not agree 

 with the facts. On May 18th, when the bulk of the controls cast their 

 first skin, they did so a day and a half ahead of the most precocious 

 member of the other lot, and the advantage thus gained was never lost ; 

 it was, on the contrary, increased so that on May 28th they were three 

 days ahead, and when pupation commenced on June 3rd they span their 

 cocoons six days earlier than their " drunken " brothers and sisters. In 

 reality this latter interval should be reduced to five days because on 

 May 30th, when all of the treated larvae had entered their last larval 

 instar, the amount of alcohol administered was so excessive that all 

 save three were stupefied and lay as if dead for 34 hours. The sponge 

 was saturated at 6.30 a.m. and the larvae affected rendered unconscious 

 by 7 A.M. When examined next day at 7 A.M., three had recovered, the 

 rest following suit before 5 p.m. the same day. 



Although possibly due to the deleterious effects of the ethyl alcohol 

 on weaker and therefore smaller larvae with their consequent destruc- 

 tion, the retardation in growth was apparently linked up to some extent 

 with the fact that the individuals exhibiting it attained a greater mean 

 size than the majority of the controls did. In consequence, they pro- 

 duced correspondingly heavier pupae and larger imagines, thereby 

 necessitating a longer period to reach their full growth. 



Of the alcoholised caterpillars, ten, comprising seven males and 

 three females, succeeded in spinning their cocoons and pupating therein ; 

 of the others, eighteen (including ten males and eight females) did like- 

 wise. The difference in sex ratios, in view of the small numbers 



