Notes in 1887 wpon lepidopterous larve, de. 551 
conclusion is also based on a very general experience of 
larve. It is therefore probable that an unusually short 
development in the egg only causes a corresponding 
protraction of the first stage. It is probable that larve 
emerge from the egg with very varying amounts of 
unassimilated nutriment, and that those with the smaller 
amounts have carried on the process of assimilation to a 
creater extent in the egg itself, and therefore emerge at 
a comparatively late period; while, conversely, those 
with the larger amounts hatch comparatively early, but 
are compelled to continue the process outside the egg. 
Hence the length of the first stage would be correspond- 
ingly greater in the latter case, but no effect would be 
produced upon the later stages. It is to be hoped that 
these possible conclusions may be tested by observations 
especially directed towards this point. 
It is probable that the length of larval life was unusually 
ereat, and that the larva becomes mature at an earlier 
period in the localities in which it breeds regularly. 
The closely-allied S. ligustrt has a larval period of about 
five weeks, and the same is true of Smerinthus ocellatus. 
In this country the leaves of the food-plant are extensively 
killed by frost during a period which corresponds to the 
last part of the larval life—a time when growth is espe- 
cially rapid. I could only obtain food by searching here 
and there in many places, and my larve would certainly 
have perished of starvation in the wild state. In addition 
to this, the larval life would have been somewhat longer 
in the latter state, for the larve were kept indoors at a 
comparatively high temperature. They were fed so care- 
fully throughout, and the food was kept so fresh, that 
there was no protraction of life owing to the causes 
which frequently operate upon larve in captivity. Tem- 
perature has a very great influence upon the length of 
larval life, as I have especially observed in the case of 
Smerinthus ocellatus during the past cold summer (1888). 
It therefore seems probable that this larva pupates com- 
paratively rarely in this country, and that in warmer 
countries the larval life is shorter, approaching that of 
S. ligustrv. 
The alternation of dark and light varieties in the suc- 
cessive stages. — This alternation was very marked in 
many larve in all the stages except the last, in which all 
the larve became dark varieties. 
