N, 
for my purpose. This made little difference in the general results, 
but had the effect of causing considerably larger proportions of 
the different lots to emerge within the shorter pupal periods, and 
above all, to increase their mass. In this way Ihave obtained some 
of enormous size; some at 65° F. (18°-19° C.) till their fourth 
skins, and then at the lower temperature, averaged in weight 
27 grammes, instead of the usual average of 18, and several 
reached 30 and even more, with a wing expanse only just under 
2 inches (fully 50 millimetres). 
[The experiments of 1910 were far from completion when this 
paper was read, so that, though the pupal weight was known and 
included in my statements, the pupal period could not be. I am 
now able to subjoin a tabular statement, which will sufficiently 
show the difference in pupal period caused by the substitution of 
65° E. (18°-19° C.) for 60° F. (15°-16° C.) as the higher temperature, 
also the difference in result caused by the order of precedence in 
which the different temperatures were applied. It will also show, 
by comparison with the information previously given as to weight, 
another fact which is not to be disregarded, viz., that the effect 
on pupal period is much less regular than the effect on weight or 
mass. 
Tabular statement. 
I. — Whole larval life at same mean temperature. 

NUMBER OF von 
MEARS. TEMPERATURES. | emerging in short 
pupal period. 


lots. | individuals. 
¡AMO = & « 3 38 54° E, (120-130 C.) I 
» 2 IS 60° F. (150-160 C.) O 
Total 1909-10. . 5 53 — I 
TONO REATO I 13 65° E. (180-190 C.) 
Oo 
Totals 1909 
and 1910 . 3 6 66 = 4 
