AND THEIR TRANSFORMATIONS. 85 
DESCRIPTION OF PLATE XXV, 
Insects.—Fig. 1. Thecla Betule (the brown hair-streak B.), female. 2. The male. 3. Showing the under side. 4. The Caterpillar. 
5. The Chrysalis. 
g. 6, Thecla Pruni (the black hair-streak B.), male. 7. The female. 8. Showing the under side. 9. The Caterpillar. 
10. The Chrysalis. 
Prants.—Fig. 11. Prunus domestica (the wild Plum). 12. Betula alba (the common Birch). 
cc Fi 
T. Betulz is from specimens in the British Museum. T. Pruni from specimens in the fine collection of Mr. Stephens. The larva of both 
are from Hiibner. The under side, fig. 3, is a female: the markings of the male are much less distinct and of a more general rust colour 
H. N. H. 

SPECIES 1—THECLA BETULZ. THE BROWN HAIR-STREAK. 
Plate xxv. fig. 1—5. 
Synonymes.— Papilio Betule, Linneus ; Haworth ; Donovan, vol. Thecla Betule, Fabricius; Leach ; Stephens ; Curtis ; Duncan, pl. 
8, pl. 250 ; Albin, pl. 5, fig. 7 ; Wilke, Brit. Butt., pl. 117 5 Harris, 27, fig. 1. 
Aurelian, pl. 42 ; Lewin, pl. 42. Lycena Betule, Ochsenheimer. 
Strymon Betule, Hiibner (Verz. bek, Schm.). 
This species being the true Fabrician type of the genus Thecla, is placed at the head of the species of Hair- 
streak Butterflies: moreover it is the largest British species of the genus, the fore wings extending from 1; to 
rather more than 1} inches; their upper surface is of a rich brown with a satiny gloss: the fore wings in both 
sexes are marked at the extremity of the discoidal cell with a short transverse black line generally succeeded in 
the males by an obscure orange cloud (which is, however, sometimes wanting), and which in the females is 
replaced by a large kidney-shaped orange patch ; the cilia is whitish; the hind wings are marked at the anal 
angle and at the base of the tail (and of the succeeding lobe of the female) with orange: there is also a minute 
white spot near the anal angle. The under side of the wings is tawny yellow, with the edge brighter orange ; 
at the extremity of the discoidal cell of the fore wings is a short transverse dark line edged with white, between 
which and the extremity of the wing is another broader dark orange wedge-shaped spot extending rather more 
than half-way across the wings, edged with a very slender dusky line, which is margined with white on the 
outside. The hind wings are somewhat richer coloured, especially near the anal angle, with an abbreviated white 
line edged externally with a dusky line extending half-way across the middle of the wing ; between this and the 
margin of the wing is another slender irregular white line, edged internally with a dusky line, the space between 
these two dusky lines being rich orange; the anal angle is marked with small black spots, and the cilia on each 
side of the tail is striped with brown. 
The caterpillar is pale green with paler oblique lines along the sides, and straight ones down the back. It 
feeds on the birch, black-thorn, plum, &c. The chrysalis is brown, with darker marks. The perfect insect appears 
in the month of August. It is by no means a common species, although widely distributed: Coombe, Birch, 
Hornsey, and Darenth woods—Raydon wood, near Ipswich—Berkshire, Dorsetshire, Devonshire, Dartmoor, 
and Norfolk—are given as the localities of this species. 
