FERTILIZATION IN THE VEGETABLE KINGDOM. 236 



to the senses and appetites of insects, secures all the advan- 

 tages with least expenditure. The earliest fertilization in 

 plants took place by the locomotion of the fertilizing or even 

 of the fertilized material, in manner of most of the Algce : 

 mainly losing this as vegetation became terrestrial, the trans- 

 portation was committed to the winds, and finally in the 

 higher plants more economically consigned to insects. 



The eleventh chapter, on the habits of insects in relation 

 to the fertilization of flowers, is one of the interesting and 

 readable although one of the shortest. It appears that the 

 prince of naturalists, Aristotle, had observed more than two 

 thousand years ago that the hive-bees visited the flowers of 

 the same species as long as possible before going to a dif- 

 ferent species. This holds true of all kinds of bees and cer- 

 tain other insects, generally, but not absolutely ; although, 

 as Lubbock has recently proved, bees are much guided by 

 color, yet they hold to the practice just mentioned in spite 

 of difference in this respect, being botanists enough to know 

 that color is not a good specific character. Mr. Darwin has 

 repeatedly seen humble-bees flying straight from a red Frax- 

 inella to a white variety, from one Larkspur to a different- 

 colored variety ; and the same as to Primroses and Pansies. 

 But two species of Poppy were by some bees treated as one ; 

 and H. Miiller traced hive-bees from blue Hyacinths to blue 

 Violets. On the other hand, Darwin's bees fly straight from 

 clump to clump of yellow Oenothera without turning an inch 

 in their course to Eschscholtzias with yellow flowers which 

 abound on either side. This constancy to species, however, is 

 manifested only when their flowers abound; a fact which may 

 have led Mr. Darwin to his explanation of the reason of it. 



" The cause probably lies in insects being thus enabled to 

 work quicker ; they have just learned how to stand in the 

 best position on the flower, and how far and in what direc- 

 tion to insert their proboscides. They act on the same prin- 

 ciple as does an artificer who has to make a half a dozen en- 

 gines, and who saves time by making consecutively each wheel 

 and part for all of them. Insects, or at least bees, seem 

 much influenced by habit in all their manifold operations ; 



