238 CALIFORNIA ACADEMY OF SCIENCES. 



directed to making a living and maintaining the species, 

 without any great regard to progress in respect to beauty. 

 Looking at it broadly, the genial climate and abundance 

 of food in the tropics has afforded a vast amount of sur- 

 plus energy to be expended, or favored katabolism, while 

 the cold climate and comparative scarcity of food in the 

 north has demanded a constant effort to accumulate 

 enough energy to preserve the vitality of the species, 

 so an anabolic state of life has prevailed. 



The birds of the tropics are, as Wallace has shown, by 

 no means universally brilliantly colored.* Indeed, he 

 questions if the proportion of brightly colored species 

 is very much greater than in more temperate regions. 

 This is due to the fact that bird life is so much more 

 profuse in these regions and there are accordingly so 

 many more brightly colored species here than in other 

 parts of the earth, that we are accustomed to think 

 of them all as being of variegated plumage. Notice the 

 enormous family of Dendrocolaptidse in South America, 

 however, in which no bright tints are developed. Still, 

 granting all this, the fact remains, that the greatest 

 variety and brilliancy of color occurs in the tropics while 

 forms characteristic of the north are seldom brightly 

 colored, and perhaps never arrayed in the splendor of 

 many tropical species. 



Mr. Frank Beddard alludes to some more special in- 

 stances of the relation between color and locality in his 

 work on Animal Coloration. f He summarises Dr. L. 

 Camerano's system of geographical colors, t as follows: 

 " The Palsearctic region — that is, Europe and Northern 

 Asia — has as prevailing tints grey, white, yellow, and 

 black; in Africa yellow and brown are most abundant; 



' cf. Tropical Nature. 



t pp. 44-47. 



t Zoologisohe Anzeiger, 1884, p. 341. 



