COLOURS OF ANIMALS. 



179 



refer our readers to Mr. Darwin's Descent of Man, 

 chapters x. to xviii., and to chapters iii., iv. and vii. 

 of my Contributions to the Theory of No.tural Selection, 

 Typical Colours. — The fourth group — of Typically- 

 coloured animals — includes all species which are bril- 

 liantly or conspicuously coloured in both sexes, and for 

 whose particular colours we can assign no function or 

 use. It comprises an immense number of showy birds, 

 such as Kingfishers, Barbets, Toucans, Lories, Tits, and 

 Starlings ; among insects most of the largest and hand- 

 somest butterflies, innumerable bright- coloured beetles, 

 locusts, dragon-flies, and hymenoptera ; a few mammalia, 

 as the zebras ; a great number of marine fishes ; thou- 

 sands of striped and spotted caterpillars ; and abundance 

 of moUusca, star-fish, and other marine animals. Among 

 these we have included some which, like the gaudy 

 caterpillars, have warning colours ; but as that theory 

 does not explain the particular colours or the varied 

 patterns with which they are adorned, it is best to 

 include them also in this class. It is a suggestive fact, 

 that all the brightly-coloured birds mentioned above 

 build in holes or form covered nests, so that the females 

 do not need that protection during the breeding season 

 which I believe to be one of the chief causes of the 

 dull colour of female birds when their partners are gaily 

 coloured. This subject is fully argued in my Contribu- 

 tions, &c., chapter vii. 



As the colours of plants and flow^ers are very diff'erent 

 from those of animals both in their distribution and 

 functions, it will be well now to consider how the 

 general facts of colour here sketched out can be 



IS- 2 



