5'M 



NATURE 



{April 2,, 1879 



to them as to lead to the rejection of a healthy and well- 

 organised mate ; yet unless this is the case, the whole 

 theory of sexual selection falls to the ground. 



Again, the general connection between coloured flowers 

 and coloured insects is by no means so general and 

 constant as Mr. Allen supposes. Perhaps the richest 

 displays of gay flowers in the world are to be found in 

 temperate Australia, in South Africa, and in the South 

 European Alps, yet in all these countries the butterflies 

 are very inferior to those of tropical forests, where flowers 

 are comparatively rare. In the forests of Para, for 

 instance, gay flowers are very scarce, as noticed by Mr. 

 Bates as well as by myself, yet the butterflies are endless 

 in their variety of lovely hues. Of course there are bright 

 flowers in the tropics, and as travellers notice these when- 

 ever they see them and also notice the handsome butter- 

 flies, it is easy to infer, as is here done, that the two 

 invariably go together. We may also remark that the 

 s£xual allurement of a peculiar odour given out by special 

 patches of scales on butterflies' wings has been disco- 

 vered by Fritz Miiller in the genera Mechanitis, Dircenna, 

 and Thecla, all very brilliantly coloured groups, a clear 

 indication that colour is not a sexual allurement, or we 

 should find it most developed, not in conjunction with, 

 but in the absence of, the attraction of odour. 



We must now pass on to the vertebrates, and we here 

 find very good evidence adduced of the existence of a 

 colour-sense in fishes, reptiles, and birds, as we should 

 expect from the known structure of their eyes ; while in 

 the case of mammals it is far less decisive. The attempt 

 to associate the brilliant colours of these animals with 

 their food and surroundings, acting through sexual selec- 

 tion, is, however, what we have now to consider ; and 

 though many alleged facts are adduced in support of it 

 several of them are as doubtful and inconclusive as in the 

 case of insects. We shall confine our attention to the 

 birds, which are the stronghold of the theory, and are so 

 much more completely known than the less highly- 

 organised fishes and reptiles. Mr. Allen claims the 

 parrots as fruit-eaters, but they are really seed-eaters, 

 their bills being specially formed to crack the shells and 

 extract and grind up the kernels of nuts and other fruits. 

 They do not therefore aid in the disposal of seeds, as they 

 feed on brown nuts or unripe green fruits from which 

 they extract the seeds, much more frequently than on 

 coloured ripe fruits. The general green colour of parrots 

 is undoubtedly protective, and this green colour is lost, 

 and vivid tints appear just in proportion as, owing to 

 various conditions, the need of concealment diminishes. 

 This is especially the case in countries where mammals 

 are few and a low type of organisation prevails, as in the 

 Australian region, in Madagascar, and in South America • 

 while in Africa and Asia, where a higher type of organisa- 

 tion prevails, the colours of parrots are more sober and 

 protective. A little further on we find the Australian 

 honey-suckers noted for their magnificent coloration ; the 

 fact being that they are decidedly a dull-coloured group 

 hardly superior to our thrushes, and not equal to our 

 finches. Yet they are as universally flower-feeders as the 

 humming-birds themselves ; and the total absence of 

 brilliant colour from these birds, which are the charac- 

 teristic family of Australia, and have been developed in 

 correlation with the brilliant Australian flora, absolutely 



negatives the idea of colour in birds being dependent on 

 the amount of colour in the food and surroundings of cer- 

 tain groups. Again, the ground-feeding pheasant family 

 are passed over as containing only one brilliant bird, the 

 peacock, whereas it abounds in species of the most 

 gorgeous colour. Such are the Impeyan pheasant of the 

 Himalayas, whose metalUc plumage is that of a gigantic 

 sun-bird ; the golden pheasant, the silver pheasant, and 

 Reeves' pheasant of China, all unsurpassed for gay and 

 conspicuous colouring ; the glorious crimson and white- 

 spotted tragopans, the elegant peacock-pheasants, and 

 the intensely brilliant fire-backed pheasants of the Malay 

 countries — together composing a group of birds whose 

 colours are unsurpassed for beauty and splendour, and 

 thus are directly opposed to the general gloom and absence 

 of colour in their habitual surroundings. 



In treating of mammals we find an equal want of 

 discrimination in estimating comparative colour and 

 conspicuousness. The tigers, the zebras, the beautifully 

 marked antelopes, and the spotted deer and giraffes, 

 which are really among the most brightly-coloured of all 

 mammals, are passed over as less beautifully coloure 

 than the squirrels and monkeys, in order to support th 

 theory that arboreal mammals feeding on fruits should be 

 (though unfortunately for the theory they are not) the 

 most brightly coloured. Monkeys, as a rule, are vei y 

 dingy brown or black, about one or two per cent, of the 

 species having patches of bright colour on the bare skin 

 of various parts of their bodies, while the nut-eating 

 squirrels as a whole are certainly not superior to the 

 grazing antelopes. In the summary of facts given a 

 pages 184 and 185 there are many errors. Scissii'ostrtir 

 Pagei does not '' belong to a family generally dull," whil 

 it is itself decidedly dull-coloured ; the " pretty cigana" i 

 a very plain coloured bird; Santarem, of which it is sai 

 " the pastures are destitute of flowers, and also of anima 

 life, with the exception of a few small plain-coloured birds, 

 is one of the richest localities for flowering shrubs in Sout 

 America, and one of the few places where I remembe 

 the conspicuously coloured fruits on many of these shrub 

 while the butterflies in the adjacent forests are gorgeov. 

 in the extreme ; and lastly, the "gay-coloured squirrel," 

 for which I myself am made responsible, is one of the 

 dullest of the group, pretty indeed as are all squirrel 

 owing to its brown and yellowish ringed tail, but in r. 

 sense whatever "gay," while I certainly say not a wor 

 about its feeding on "bright-coloured fruits." 



Such mistakes as these pervade this portion of th 

 work, and are made the foundation for repeated argi 

 ment and illustration ; and they serve to show how in 

 possible it is even for the most earnest and enthusiast: 

 student to make a few months' labour suffice for a correc 

 appreciation of the bearing of the overwhelming mass c 

 facts presented by the countless species of the animal an 

 vegetable world. I have marked a number of other pa 

 sages to which I altogether demur, but many of thei 

 involve arguments Avhich would extend far beyond tli 

 limits of an article. For the same reason I can on! 

 briefly refer to the concluding chapters on the " Color 

 Sense in Man," in which the theor}' of Mr. Gladstone 

 and the German philologists is disproved in a mannei 

 which is absolutely conclusive. 



In the summary and recapitulation we find all the fact 



