BUTTERFLIES AND MOTHS 327 



the Pale Clouded Yellow (Colias liyale) and the Brimstone (Gonepteryx 

 rhamni), in which the wings are of a light yellow (male) or greenish- white 

 (female). Compared with these, the Swallowtail Butterfly (Papilio 

 machaon) is of very variegated colours. Although abundant on the 

 Continent, it is rare now in England. 



On stinging-nettles may be observed frequently black caterpillars 

 with white dots, which are beset with numerous spiny hairs ; the 

 protective significance of these structures is sufficiently borne out by 

 the fact that caterpillars provided with spines or hairs are despised by 

 all birds, with the exception of the cuckoo (which see). When the 

 period of transformation to the pupa stage arrives, the larva spins 

 several threads, by which it fixes the posterior end of its body, so that 

 the head hangs downward. The pupa also remains suspended in this 

 position, being attached to the silky web by two fine hooks developed 

 at the posterior end. At the proper time there escapes from it a very 

 handsome butterfly, which has been called the Peacock (Vanessa io), 

 from the beautiful eye-like marks, composed of a variety of colours 

 on a brown ground, which ornament the wings. The under side of the 

 wings, however, is of very inconspicuous colouring (dirty brown with 

 darker dentated lines) ; hence, when sitting on the trunk of a tree, the 

 butterfly can scarcely be distinguished from the bark. The same 

 phenomenon is repeated in other closely related species, viz., the Red 

 Admiral (V. atalanta), the Camberwell Beauty (V. antiopa), the velvety 

 brown wings of which are ornamented with a row of blue marginal spots 

 and a yellow border, and the Large and Small Tortoiseshell (F. poly- 

 chloros and urticce), etc. 



Anyone who has watched the butterflies known as the Blues (Lyccena} 

 and the Dark Green and Queen of Spain Fritillaries (Argynnis 

 aglaia and latonia) fluttering along roads, forest-glades and heaths, must 

 have noticed with astonishment how these beautiful creatures will 

 suddenly disappear before his eyes as though they had sunk into the 

 ground. One sees the insects settling on a flower to drink in its nectar, 

 or alighting upon the ground to rest, or settling in the grass to sleep, 

 and it is only with the greatest difficulty that one can rediscover them, 

 since not a trace is to be seen of their multicoloured upper sides. The 

 under side of the Blues is grayish-yellow or brownish, sprinkled with 

 white-bordered black dots, while in the Fritillaries the ground colour is 

 pale and sprinkled with numerous spots of silvery or mother-of-pearl- 

 like brilliancy. One might expect these spots would render these insects 

 very conspicuous. But the mere fact that they are only found on those 

 parts of the insects (hind-wings and tips of the fore-wings ; see cabbage 

 white) which are visible during rest should cause us to reflect ; whilst 



