DOMESTICATED INSECTS 251 



the question of evolution. The various breeds were studied 

 with the utmost thoroughness by Darwin, and more recent ob- 

 servations show that the subject is by no means exhausted, and 

 that these birds are most desirable subjects for experiment when 

 heredity problems have to be considered. 



THE AFRICAN OSTRICH (STRUTHIO CAMELUS). Although 

 ostriches have been domesticated or semi-domesticated by some 

 of the native tribes of Africa from remote times, the " ostrich 

 farms" of the south are of comparatively recent date (fig. 1182). 

 The inducement to this industry is of course found in the valu- 

 able plumage, the white wing -feathers being most esteemed, 

 while those of the tail and also some of the back plumes are 

 also marketable. Birds are in their prime when from three to 

 four years old, and the feathers of the males are of better 

 quality than those of the females. They are plucked or cut off 

 about twice in three years, and are subjected to a number of 

 processes before being fit for use. Ostrich-feathers constitute an 

 important export from Cape Colony, yielding not far short of a 

 million pounds sterling annually. The industry has been intro- 

 duced with more or less success into several other parts of the 

 world, notably Southern California and Australia. 



DOMESTICATED INSECTS (INSECTA) 



Under this heading may be placed the Honey -Bee (Apis 

 mellificd}, the Silk- Worm Moth (Bombyx mori, &c.), and the 

 Cochineal Insect (Coccus cacti). The industries which these 

 insects render possible are all of ancient date, and the two first 

 of very considerable importance. 



THE HONEY-BEE (Apis MELLIFICA). A liking for sweet 

 things is a wide-spread human weakness, and appears to be of 

 very old standing. Wild bees of different kind are native to 

 many parts of the world, and the honey which some of them 

 store in abundance no doubt soon attracted the attention of 

 primitive peoples, whose most important business in life con- 

 sisted in the discovery of edibles (compare vol. ii, p. 63). Of 

 a small Brazilian species Bates says (in The Naturalist on the 

 Amazons]'. "A hive of the Melipona fasciculata, which I saw 

 opened, contained about two quarts of pleasantly-tasted honey. 

 The bees . . . have no sting, but they bite furiously when their 



