ow Vanessa and other Lepidoptera. 431 
twenty-nine days or more, are very like IV.a ; iced for that ora 
longer period, they are darker; in all cases they show a return of 
the yellowish markings. 
Class V.b (iced at 33°, fourteen to forty-two days, then at various 
temperatures, such as cellar at 59°, emerging in twenty-seven to thirty 
days ; or refrigerator at about 49°, six to thirty-two days, and then 
in cellar or room, emerging in twenty-one to two days more). These 
are classed together, because the effects seem to depend on the 
duration of the icing. No great effect is produced under twenty- 
nine days’ icing ; the extreme darkness, often without crippling, is 
produced by icing thirty-six days, followed by the refrigerator 
at 49°, for six to nine days (Plate IX., fig. 3); but some taken 
straight from the ice to the cellar are nearly as dark. Of those 
iced from thirty-eight to forty-two days nearly all died, or were 
more or less crippled ; one of the latter has nearly all the four spots 
on the forewings obliterated ; and it may be observed that the 
icing for thirty-six days or more, followed by the refrigerator, 
which produces the extreme dark effect, has a tendency to cause 
the normal spot near the inner edge, which is nearest the base of 
the forewing, to disappear. 
As regards the general appearance of those which show the 
extreme effect of the low temperature, it may be said that they 
much resemble V. xanthomelas. [Tendency to formation of new 
dark spots continues. An additional dark spot may also appear in 
cell (forewing) below “I” and “II.” The border may become 
uniformly dark. ] 
A second company of V. polychloros, just changing their last 
skin, reached me on the 2nd June, also on sallow. Sleeved on 
cherry they did very well. Some were forced, emerging in six and 
a half to seven days. Others, placed out of doors at a temperature 
ranging from 67° to 59°, averaging about 64°, emerged in sixteen 
to seventeen days. This was a rather lighter coloured company 
of butterflies. There is the same kind of difference in appearance 
between the forced and the others, as there is between Classes I. 
and II. of the first company, but it is less in quantity. 
V. polychloros, general conclusions. The colouring is 
considerably affected by temperature in the pupal stage, 
low temperatures producing a deepening of the ground 
colour and an extension of the dark markings; and high 
temperatures producing a lightening of the ground colour 
and an extension of the yellowish markings. The blue 
and bluish markings are strongest in those at moderately 
