AND THEIR TRANSFORMATIONS, 105 
SPECIES 6.—POLYOMMATUS CORYDON. THE CHALK-HILL BLUE BUTTERFLY. 
Plate xxxiii. fig. 4—8. 
Synonymes.— Hesperia Corydon, Fabricius ; Hiibner, Pap. pl. 59, | Wood, Ind. Rat. pl. 2, fiz. 65. 
Dunean, Brit. Butt. pl. 32, fig. 3. 
286—8. Lewin’s Pap. pl. 36, figs. 1, 2,3. Donovan, Brit. Insects, | Agriades Corydon, Hiibner (Verz. bek. Schmett. ) 
pl. 231, f. 1, male, Esper. Schmett. t. 33, fig. 4. Papilio Tiphys, Esper. Pap. pl. 21, cont. 1, fig. 4. (Female.) 
Polyommatus Corydon, Latreille ; Stephens; Jermyn; Curtis; | Papilio Calethys, Jermyn, 2d Edit. p- 169 (variety). 
This species varies in the expansion of its wings from an inch and a third to more than an inch and a half. 
The male has the upper surface of the wings of a very light silvery blue, with the outer margin and Veins dusky ; 
close to the outer margin is a row of black spots, which are almost suffused with dark margin of the fore wings, 
but are more distinct in the hind pair, two at the anal angle being smaller and close together ; these spots are 
more or less annulated with silvery white. The fore wings in this sex are of a greyish white on the under side, 
with five rows of spots, four towards the base in pairs, one larger, and one smaller in each; then a transverse 
nearly straight row of four spots, of which the inner one is doubled, succeeded by a curved row of four spots 
towards the costa, then two submarginal rows of dots, the inner ones being the largest, forming an interrupted 
bar, and the outer ones rounded and subocellated ; the tips of the veins, and of the cilize opposite to the veins, are 
marked with dark spots ; the dise of the hind wings is of a pale-greyish brown hue, the base strongly saturated 
with greenish blue, each marked with about twenty blackish ocellated spots, an almost blind white spot at the 
extremity of the discoidal cell, the space beyond the two middle spots in the outer curved series is also white. 
Seven or eight of the terminal spots are ocellated, each being preceded by an angular black mark, and a 
small patch of orange colour; the extreme edge of the wing is also blackish, and the fringe is white. 
The female differs from the male in having the upper surface of the wings of a brown colour, with a small 
paler spot in the middle of each, that in the fore wings having a black pupil; moreover, there is a submarginal 
row of ocelli having the pupil black, surrounded by a whitish iris, the upper part in the hind wings being orange ; 
these ocelli are also sometimes preceded by a row of almost obsolete pale lunules ; in some specimens, however, the 
appearance of these ocellated spots is almost lost; on the underside the ground colour of all the wings is 
considerably darker than in the males, and the ocelli are much more distinct ; they are, however, similar in their 
number and situation to those of the male, but the fringe is more strongly marked alternately with brown. 
There are a number of varieties in our cabinets resulting from the greater or less distinctness of the ocelli, 
and the greater suffusion of brown over the wings of the male. One of these varieties having the wings “ above, 
brown with a blue disc, and a whitish discoidal dot with a black pupil; beneath, the posterior wings have a 
discoidal, white, cinctured crescent, with a waved band of seven undulated spots towards the hinder margin,” 
constitutes the Polyommatus Calethys, of the second edition of Miss Jermyn’s Butterfly Collector’s Vade mecum. 
The caterpillar is green, with yellow dorsal and lateral lines. It is stated to feed upon the wild thyme. The 
perfect insect appears in July. It is local in respect to the districts in which it is found, especially frequenting 
chalky places. In such places it is, however, very abundant. From Dover, along the southern coast near 
Shoreham, Newport, in the Isle of Wight, and near Darenth Wood in Kent, various parts also of Suffolk, 
Oxfordshire, Cambridgeshire, are recorded as its localities. It is also ‘very abundant on the hills above 
Prestbury, near Cheltenham, and near Winchester. A single specimen was also taken a few years ago near 
Knowle, Warwickshire,” as we are informed by the Rev. W. T. Bree. 
