26 BRITISH BUTTERFLIES 
of July; but there is evidently no regularity in the broods, as may be seen from the following result of the 
observations of Jacob L’Admiral of the dates in which specimens of this species spun their webs, became pupe, 
and appeared as butterflies, with the number of days in which they remained as pupe. 
SPON. WIERD EEN POPJE. EN KAPEL, IN DAAGEN. 
De eerste, 18 July, 1720. 20 July. 5 Augustus, — 16 
De 2de, 6 July, [Juny 2] 1728. 8 Juny. 19 Juny, — ill 
De 3de, 13 September. 16 September. 1 April, — 197 
De 4de, 2 September, 1739. 4 September. 23 September— 19 
De Sde, 2 September. 5 September. 28 May, — 265 
Like P. Brassicx, this species inhabits the whole of Europe, from Lapland to the south, and is found in 
Egypt, Barbary, Asia Minor, Siberia, and Cachmere. The P. Ergane, Hubn. (P. Narcea of Dahl and Treitschke), 
and the P. Nelo of Borkhausen, are probably varieties of this species. 

SPECIES 4.—PIERIS METRA. HOWARD’S WHITE BUTTERFLY. 
Plate v. fig. 5, 6. 
Synonymrs.—Pontia Metra, Stephens’ Hlust. Brit. Ins. Haustell, | 
vol. i. p. 19 and 146. Duncan Brit. Butt. pl. 8, fig. 2 | Female—Papilio alba media trimaculata, Petiv. pl. 1, fig. 
Male— Papilio alba media immaculata, Petiver Pap. pl. 1, fig. 11, 12. 
3, 14. 
This supposed species bears the same relation to P. Rapw as P. Chariclea does to P. Brassicee, differing 
from it in its smaller size, varying from twenty to twenty-five lines in expanse, and being also early in 
appearance, the first brood being found early in April, or even at the middle of March. In the appendix to his 
work, Mr. Stephens questions whether this or P. Chariclea be double-brooded, as out of several hundred specimens 
taken in July and August, not one belonged either to P. Metra or Chariclea, but to P. Rapw and Brassice. 
P. Metra is very variable in its markings, but is generally distinguished from P. Rapw by the comparative 
slenderness and truncation of the fore wings, which are consequently very acute at the apex, which is slightly 
clouded with dusky ; and by the black base of the wings. ‘The male has a single obsolete dusky spot, and 
the female two, that at the anal angle being geminated; this sex has also the basal half of the wing 
much clouded with dusky: the posterior wings in both sexes are white, with the base black, and a dusky costal 
spot. Beneath, the sexes are similar; the anterior wings are white, with the tip yellow; the base and two 
obsolete spots dusky ; the posterior wings are bright-yellow, with a pale-orange streak on the costa, strongly 
irrorated throughout with dusky, the anterior half of the discoidal cell being least speckled ; the antenna, legs, 
and body, resemble those of P. Rape ; the cilia are entirely clear, white” (Stephens). Mr. Stephens describes 
two varieties of the male, in which the markings are less distinct, or even almost entirely obliterated. He also 
in his appendix mentions several circumstances in support of the specific distinction of these early “ small whites ;” 
and states, that the present had long been known amongst collectors under the name of “ Mr. Howard’s white.” 
If indeed it be admitted that these “early whites” exhibit such distinctions of form, size, colour, and markings, 
it seems impossible to suppose that their detention in the chrysalis through the winter months should have the 
effect of producing such striking peculiarities. The caterpillar has not unfortunately been yet observed, “ but the 
chrysalis does not materially differ from that of P. Rapx ” (Stephens). 
