3°6 
PIERIDAE 
Down each side is a very pale, indistinct spiracular line, on 
which is situated a series of bright gamboge-yellow marks, 
one on the second and third segments/and two on each of the 
other eight segments ; the last is without any. The spiracles 
are flesh-coloured outlined by black. The entire surface is 
thickly sprinkled with small black points, varying in size, 
some extremely small; each emits a very fine, short, pale- 
coloured hair. The head is green and sprinkled with points 
and hairs similar to those on the body ; the eye spots are 
black. The larval state occupies twenty days. 
Pupa. The pupa is attached by a fine silken cincture 
round the middle, and by the cremastral hooks to a pad of silk. 
The normal sites for pupation are under copings on walls, 
ledges of sheds, palings and buildings generally. The colouring 
of the pupa, which is highly sensitive to backgrounds, usually 
harmonises with its surroundings. The pupae resulting from 
the spring parents are frequently attached to the leaves of 
the food plants, when they are invariably green, rendering 
them difficult to detect. 
The colour varies greatly in different specimens and is more 
or less in harmony with the surroundings ; it ranges from 
cream-white, buff, pale drab, to dull grey or dusky. In other 
specimens it varies from pale ochreous to green. Numerous 
black dots are scattered over the surface of the pupa, and 
along the beak of the head is a conspicuous black streak. 
The pupa averages 19 mm. long. The head has a frontal 
beak; the thorax has a strongly-angulated dorsal keel; 
the abdomen terminates in a long cremaster provided with 
hooks; and along the ventral surface the wings form a slight 
swelling, otherwise the outline is almost straight. The pupal 
state of those that hibernate lasts from six to eight months. 
Imago. The average expanse of the wings is 50 mm., but 
the Small White varies in size ; small specimens sometimes 
measure only 38 mm. and large ones, as much as 57 mm. 
There is a distinctive sexual difference both in colouring 
and in markings. 
Male . Glaucous-white; the apex of the fore wing is 
black or grey; there is a single black spot near the 
middle of the wing, arid the hind wing has a black spot 
on the costa ; the base of all the wings is powdered with 
