9^4 



THE NATURE BOOK 



IHELLA tjCERCLS CATERPILLAR. 

 (Magnified.) 



tree. Its scientific name is Thecla qucrcits, 

 while it is known popularly as the Pui"ple 

 Hairstreak or the Oak Thecla. There is 

 scarcely an oak wood in England, at 

 least in the south, which is not graced in 

 summer-time by the presence of this 

 butterfly ; while it is well known in Ireland 

 and in many parts of Scotland. 



Beside being the commonest member 

 of its genus, it is incUsputably the most 

 lovely. Let me briefly describe its 

 charms. The outline of the wings is 

 somewhat angular, owing to the costal 

 and hind margins being nearly straight, 

 while the tip, or apex, is only very slightly 

 rounded. The outer margin of the hind- 

 wing is slightly scalloped, and bears the 

 Uttle "tail" already referred to. The 

 ground colour of the wings, on their upper 

 surface, is brownish black, in the males 

 overlaid, so to speak, with a rich purple 

 gloss, save for a narrow area at the 

 margins. In the female, this purple gloss 

 is confined to a patch which occupies a 

 portion f)nly of each fore-wing ; but while 

 abbreviated in its extent, the colour is 

 more rich and deep, and reflects the light 

 in a manner reminiscent of the Purple 

 Emperor's glorious sheen. 



In both sexes, the under surface of the 



wings is a delicate ashen grey, inclining 

 to pale brown in the males. Stretching 

 across the wing-area is a white hue, edged 

 with brown, which, in the hind-wing, 

 makes a kind of double twist, so that it 

 assumes somewhat the fonii of the letter 

 W. In the case of a rarer Hairstreak 

 butterfly, this curious mark is so character- 

 istic as to ha\'e suggested both the popular 

 and the scientific names, to wit, the\\'hite 

 Letter Hairstreak (Thecla W-album). 

 The magnified photograph of the Purple 

 Hairsticak Butterfly, newly emerged from 

 the pupa, and hanging from a twig, gives 

 some idea of the beautifid under surface 

 of the wings and of their delicate marginal 

 fringing. But a photograph fails altogether 

 to suggest the exquisite softness of the 

 colour scheme, or the two orange spots, 

 one being black centred, which adorn the 

 anal area of the hind-wing. 



The Purple Hairstreak Butterfly is on 

 the wing in July and August. In the 

 fomier month the eggs are laid by the 

 female on the twigs of the oak {Qiierctis 

 robiir). Here they remain throughout the 

 winter, exposed to the inclemencies of 



THECLA QVEHCVS CATERPILLAR. 

 (Natural size.) 



