424 THE DESCENT OF MAN 



to the females, and thus gratify their deep-seated preference 

 for the normal color of the Order to which the Leptalides 

 belong." 



Bright Colors of Caterpillars. — While reflecting on the 

 beauty of many butterflies, it occurred to me that some 

 caterpillars were splendidly colored; and as sexual selec- 

 tion could not possibly have here acted, it appeared rash 

 to attribute the beauty of the mature insect to this agency, 

 unless the bright colors of their larvae could be somehow 

 explained. In the first place, it may be observed that the 

 colors of caterpillars do not stand in any close correlation 

 with those of the mature insect. Secondly, their bright 

 colors do not serve in any ordinary manner as a protec- 

 tion. Mr. Bates informs me, as an instance of this, that 

 the most conspicuous caterpillar which he ever beheld 

 (that of a Sphinx) lived on the large green leaves of a 

 tree on the open llanos of South America; it was about 

 four inches in length, transversely banded with black and 

 yellow, and with its head, legs, and tail of a bright red. 

 Hence it caught the eye of any one who passed by, even 

 at the distance of many yards, and no doubt that of every 

 passing bird, 



I then applied to Mr. Wallace, who has an innate genius 

 for solving difficulties. After some consideration he replied: 

 "Most caterpillars require protection, as may be inferred 

 from some kinds being furnished with spines or irritating 

 hairs, and from many being colored green like the leaves 

 on which they feed, or being curiously like the twigs of 

 the trees on which they live." Another instance of pro- 

 tection, furnished me by Mr. J. Mansel Weale, may be 

 added, namely, that there is a caterpillar of a moth which 

 lives on the mimosas in South Africa, and fabricates for 

 itself a case quite indistinguishable from the surrounding 

 thorns. From such considerations Mr. Wallace thought it 

 probable that conspicuously colored caterpillars were pro- 

 tected by having a nauseous taste; but as their skin is ex- 



