A NATURALIST IN BRAZIL 



whose underside they are laid. The caterpillars assume the colour 

 of their environment ; diagonal or longitudinal stripes add to the 

 difficulty of detection. Many caterpillars feed only at night, and by 

 day, as I have already described, gather together in great clusters, 

 which mimic the bark of trees, or merely arouse distaste. The large 

 caterpillars of certain of the Bombycidae (Hyperchiria) or Silk- 

 moths have jet-black bodies, on which the yellow hairs have an 

 uncannily vivid appearance. We have already seen that black and 

 yellow are warning colours, and as a matter of fact these caterpillars 

 burn the fingers if they are handled. Before pupation they spin a 

 cocoon. In the emerging moth the upper surface of the fore-wing is 

 shaped and coloured like a leaf, but the hind-wings bear great eyes, 

 which are so finely shaded that they seem actually to stare from 

 the wings, and many birds might well be frightened if their intended 

 victim were suddenly to unfurl its hind-wings. 



Other caterpillars construct a sort of bag with small fragments 

 of wood, and spin their silk around it. The body of the caterpillar 

 remains inside the bag. I found one species whose bag was as big as 

 one's finger, and hung downwards in a singular fashion when its 

 wearer crawled along a twig. 



The largest of all the Lepidoptera is a native of Brazil : the Great 

 Owl moth, whose wings have a span of 1 1 inches. Despite its great 

 size, the sitting moth is very difficult to detect, since its white 

 wings, covered with wavy lines and specks of black, resemble the 

 bark of a tree. It is said to be so shy that it flies off" at the slightest 

 crackle of a twig; so that the Indians shoot it with the blowpipe. 



Since the wings of butterflies are particularly well adapted to 

 assume the shape and colour of withered leaves, we need not be 

 surprised that Nature has employed this means of protection. It is 

 true that Brazil has no such perfect mimics of foliage as exist in 

 India, where the Kallimae imitate leaves so perfectly as absolutely 

 to defy detection, but the South American families of the Anaeae 

 and the Siderones nevertheless have remarkable gifts of mimicry. 

 When these insects fold their wings they assume the likeness of a 

 brown, yellow or green leaf, traversed by a few rather faint veins. 

 A few specks of mildew have not been forgotten. In flight, the butterfly 

 shows the vividly-coloured upper surface of its wings : brown and 

 blue, with light-blue spots, or red and yellow, or dark-red, enlivened 

 by bright-red cross-kernels. 



As sting-bearing insects the Wasps and Bees have no need to 

 conceal themselves; but they are, as we have seen, the models for 

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