THE MOSAIC OF COLOURS 



of every species, destroying a butterfly each time. One experiment 

 with one species is enough; the other species, which have much 

 the same appearance, will profit by it. 



But the scientist who turns his attention to the protected butterflies 

 of Brazil may discover still more remarkable facts. When Bates, 

 who, in the middle of the nineteenth century, spent eleven years 

 in exploring the banks of the Amazon and its tributaries, swept his 

 net one day through a swarm of Heliconiinae, he found, to his 

 surprise, that he had caught a butterfly which looked like a Heli- 

 conius, but revealed a different innervation of the wings. The various 

 groups of butterflies are recognized by this innervation, and the 

 wings of the captured butterfly showed that it belonged to quite 

 another group ; namely, to the Pieridae, which have many represen- 

 tatives in Europe. Being on the alert. Bates, and subsequently other 

 explorers, looked into the matter, and to-day we know that there 

 is a whole family of South American Pieridae which bear a striking 

 resemblance to the protected butterflies, and in shape and colouring 

 are quite unlike the rest of the Pieridae. Their wings are long and 

 narrow; one species, Dismorphia orise (Plate 29, I, 9), has, like 

 Methone, glassy yellow wings, rimmed with black; another, Dis- 

 morphia or Leptalis amphinoe, has black, ochreous, and yellow 

 markings, in imitation of the Mechanitis butterflies (Plate 29, I, 6), 

 while other species have selected other models. In many of the 

 Pieridae the form and colouring are such that one can no longer 

 recognize their descent, but in Dismorphia orise we see, on the 

 upper part of the hind-wing, a last vestige in the shape of a white 

 dust (9), while in Dismorphia arsinoe the female has no charac- 

 teristics of the Pieridae, although the male has a considerable white 

 patch on the hind-wing (5). Still more conspicuous is the difference 

 in the case of Perhybris pyrrha (Plate 29, I, 2, 3). Here the female 

 has clothed herself entirely in the black, brown and yellow costume 

 of the protected butterflies, while the male is an obvious Pierid, 

 very like our Cabbage White. But if one turns him over one sees 

 on the underside of the hind- wing an ochre-brown stripe edged 

 with black, the beginning of the Heliconius livery. 



Bates, nearly eighty years ago, recognized the fact that these 

 Pieridae had probably adopted their colouring for protective 

 purposes. The Pieridae are highly appetising butterflies; in many 

 species, indeed, the males are fragrant as flowers. They are therefore 

 eagerly devoured by birds, lizards, and other enemies, and only their 

 rapid multiplication makes up for their losses. In Brazil, however, 



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