Darwin on the Effects of Cross- and Self Fertilization. 139 



tation 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 flower.-, is one of the interesting and readable, 

 although the shortest. It appears that the prince of naturalists, 

 Aristotle, had observed more than 2000 years a.uo thai the hive- 

 bee visited the flowers of the same species as long as possible 

 before going to a different species. This holds true of all kinds 

 of bees and certain 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 

 rraxineJla to a white variety, from one Larkspur to a different 

 colored varietv. and the same as to Primroses and Pansies. 

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

 and H. Midler traced hivi-l.ees from blue hyacinths to blue 

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

 clump to clump of a yellow (Enothera without turning an inch 

 from their course to 'Kscliseholtzias 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 learnt how to stand in the best position 

 on the flower, and how far and in what direction to inset their 

 pi--l„ 1 <,-i ( les.* They act on the same principle as dees an artificer 

 who has to make half-a-dozen engines, 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; and we shall presently s 



orolla." (p. 42a) 



As to this latter practic 



• biting* holes through the 



«. They were twice as many 



as I could judge, of a Staehys and Pentste,„o>i by 

 ■ upper surface of the enroll,-, and sucking through 

 lan by entering in the proper way. Nevertheless 



i i< 

 e_'h both eaivx nd mlla This iction tliei fore 

 t. of which faculty we have abundant evidence in 



