202 
NYMPHALIDM. 
there is practically no night, butterflies are continuously on the 
wing, supposing the sun’s face not to he obscured by clouds or 
passing snow-showers. Furthermore, he told me that about one 
month in each year is the longest period in which it is possible for 
these insects to appear in the perfect state, and that about six 
weeks is the limit of time allowed to plant-feeding larvae ; during 
all the rest of the year the land being under snow and ice. This 
latter fact is suggestive as showing the conditions under which the 
species maintain their existence. We have, however, much yet to 
learn respecting their life-history. The intense cold is not of great 
importance. We know already that larvae may be frozen till they 
are as brittle as rotten twigs, and still suffer in no way. The 
principal point may be put as follows ; ~ Is there sufficient time in 
each year for a larva to hatch from the egg, feed up, and change to 
a chrysalis ? The continuous day no doubt acts beneficially in 
this respect on the larvae of butterflies, such as Colias and Arfjijnnis, 
which probably feed only in the daytime ; but it must act in a con- 
trary manner on those of Noctuae, &c., which practically feed only at 
night. Upon reviewing all these conditions, I am disposed to think 
that more than one year is necessary in most of the species for the 
undergoing of all their transformations. This indeed is already 
suspected in certain species that inhabit the boreal and alpine 
portions of Europe.” 
8. — A. Freija, Thub. Diss. Eut. 2, p. 34, T, fig. 14 (1791); 
Hiib. 55, 56, 771-2; Esp. 109, 1; 0. I. 1, 78; 
l)up. i. 19, G, 7 ; Err. 295, 3. 
Papilio Dia lapponica, Esp. 97, 3. 
Expands from 1-30 to 1’75 in. Wings dull fulvous, black at 
the base, and with the usual black spots rather larger than in the 
last species. Underside: Hind wings reddish brown; there are 
generally some yellowish spots near the base, and a discoidal spot 
of yellowish white, with a black spot; on the central light band are 
two or three white triangular spots, the band itself being bordered 
with a more or less distinct zigzag dark line ; hind-marginal white 
s])ots triangular ; the row of spots internal to these not black, but 
very nearly the same as the ground colour. PI. XL VII., 7. 
