AND THEIR TRANSFORMATIONS. 15 
SPECIES 1.—COLIAS EDUSA. THE CLOUDED-YELLOW BUTTERFLY. 
Plate 2, fig. 1, 2, 3, 4, and 8 
Synonymes.—Papilio Edusa, Fabricius Ent. Syst. v. iii., part 1, p. Papilio Hyale, Esper. Donovan Brit. Ins. 2, pl. 43, fig. sup. ¢. 
206. Donovan Brit. Ins. 7, pl. 238, fig. 2 (female). Harris Aurelian, Papilio Electra, Lewin, pl. 32 (and Linn, Syst. Nat. ii. 764, teste 
pl. 29, fign. g, fig. m. 9. Newman Ent. Mag. 1, 85). 
Colias Edusa, Stephens, Curtis, Duncan Brit. Butt. pl. 5, fig. 2. 
The expansion of the wings of this species varies from nearly two inches to two inches and a half. The 
upper surface of the disc of the wings in both sexes is a rich orange colour, the males having a round discoidal 
black spot on the fore wings, and a broad black apical margin irregularly toothed within, extending through both 
wings, with several narrow orange lines running through the black border, indicating the place of the nerves ; 
the dise of the hind wings is somewhat darker, with a large discoidal brighter-coloured orange patch. The upper 
side of the female differs in having the broad apical border marked with several irregular yellow spots, 
and more indistinctly indicated in the hind wings, which are darker and yellower than in the males. 
Beneath, both sexes are nearly alike, the disk of the fore-wings being lighter orange, with a black discoidal 
spot, the margins greenish, with a row of blackish spots at some distance from the apical margin ; the hind wings 
are greenish, with a round silver discoidal spot surrounded with red, and accompanied by a smaller silvery dot ; 
between this and the apical margin is a row of brownish red dots. Most modern Entomologists are agreed in 
regarding the Papilio Helice of Hubner and Haworth, figured by Stephens (Illustr. Haust. pl. 2*, and our fig. 8), 
as a variety of the female of Colias Edusa, from which it differs in having the ground colour of the disc of the 
wings, as well as the spots in the black apical margin, yellowish white. No corresponding variety of the 
male has yet been observed. The insect figured in the next plate, under the questionable name of Colias 
Chrysotheme, has also been regarded by Mr. Curtis as a variety of C. Edusa. 
The caterpillar of C. Edusa, which feeds upon Medicago lupulina, various species of Trifolium, and other 
leguminous plants, is green, with a lateral stripe varied with white and yellow, and with an orange dot on 
each segment. The chrysalis is green, with a lateral yellow line and several ferruginous dots. 
Boisduval gives Europe, Egypt, the coast of Barbary, Nepaul, Cachemere, Siberia, and North America, as the 
localities of this species. Mr. Burchell is stated by Mr. Duncan to have found it in South Africa ; but this I 
apprehend must have been the species described by Boisduval, from the Cape of Good Hope and Caffraria, under 
the name of C. Electra of Linnzus, by whom also the Cape of Good Hope was given as its locality. Hence, 
from the similarity of the two species, it is that I have hesitated to consider our English species as the true 
C. Electra, as stated by Mr. Newman. 
This is one of those species of butterflies whose periodical appearance (every three or four years, as stated by 
some writers) has so much perplexed Entomologists. Various opinions have indeed been suggested by authors, 
in order to account for this singular circumstance,—such as the failure of their natural enemies, the 
Ichneumonidz, or insectivorous birds—an increased temperature—or the dormant state of the eggs until called 
forth by some latent coincidences. All these opinions are, however, but merely conjectural ; nor can the matter 
be cleared up until a more minute inquiry into the habits of the species has been made. 
