432 Mr. I. Merrifield on Temperature Hxperiments 
low temperatures, Classes III. and IV., in many of which 
they form some rather bright crescents on the forewings ; 
but at the extremely low temperatures they tend to be 
supplanted, in some cases entirely so, by black. 
[Forcing invariably tends to produce yellow, whether 
pupa previously warmed or cooled. Refrigeration pro- 
duces increased breadth of dark brown, whether followed 
or not by forcing.|_ Imay add that among the specimens 
I exhibit, one belonging to Class LV.a (refrigerator thirty- 
eight days, then cellar four days, and forced three days) 
(Plate IX., fig. 2), to which my attention has been directed 
by Dr. Dixey’s observations, is particularly interesting, 
showing “ Series D” as a nearly complete chain of faint 
yellowish spots, or rather clouds, on both forewings and 
hindwings, the anterior three or four on the forewings, 
and all those on the hindwings having each a small black 
point in the centre. It seems as if it required cold, 
succeeded by heat, to cause this chain of yellowish spots 
centred with black to be brought out. 
Nothing has been said about the colouring of the 
under sides. ‘This varies moderately in darkness or 
lightness, but I have not been able to associate this 
variation definitely with temperature. 
Vanessa atalanta. In looking carefully, and aided by 
a strong light, at the V. atalanta upon which experiments 
were made in 1892, as recorded, Trans. Ent. Soc. Lond. 
1893, pp. 58-62, I noticed a feature which had escaped me 
before, viz., that eight out of the ten which were subjected 
to the high temperature of 80°-90° had a few dull orange 
scales on the upper side of the forewings, between the 
large white costal blotch and the row of smaller white 
spots nearer the hind margin. 
I determined to develop this tendency by exposing 
some pup to a greater heat. The effect was a great 
development of this orange colour, both in intensity, it 
becoming distinctly scarlet, and in quantity, so as to form 
a scarlet cloudy patch sufficient to attract attention on 
casual observation. I exhibit several examples. This 
patch is between the large white costal patch and the 
third of the row of white spots beyond, and tends to form 
a scattered ring around this third spot; other scales, from 
golden brown to scarlet, are developed along the outer 
part of the costa and near the base, and elsewhere on the 
forewing. 
