The Life of the Individual 119 



such flowers than on other flowers a quarter or half mile 

 away. 



On one occasion, the author watched a head of white 

 clover within two feet of a hive entrance. This flower was 

 without a visitor for so long that it was almost concluded 

 that there must be no nectar in it. All this time hundreds 

 of bees were flying to and from the hive, many of them pass- 

 ing within six inches of the flower. Finally, a bee flew from 

 the entrance directly to this flower and worked for a con- 

 siderable time, sucking nectar, and, evidently getting a 

 sufficient quantity after a time, it returned to the hive. That 

 there was considerable nectar present in this flower is shown 

 by the fact that other visits were made to this flower within 

 the next half-hour from the same hive. At no time, in an 

 hour's observation, were two bees on the head at once. 



Furthermore, when a bee flies from the hive, the flight 

 is usually not uncertain but is directed toward a source of 

 supply. It is usually stated that bees carry either nectar 

 or pollen back to the hive but not both, but this is not cor- 

 rect. It may perhaps be stated that they usually gather 

 from one species only on any given trip. 1 Some additional 



1 This feature is of the highest importance in a consideration of the 

 value of the bee in the cross-pollination of plants. Since the trips are 

 usually confined to one species, the beneficial results are increased many 

 fold, for if they wandered promiscuously from one to the other species 

 they would thereby scatter pollen where it would be ineffectual. That 

 they fail to discriminate among various varieties may be considered as 

 not a misfortune since certain varieties are pollinated better with pollen 

 from another variety. 



Bulman (1902, The constancy of the bee, Zoologist, Ser. 4, VI, pp. 

 220-222) quotes from various authors to the effect that bees keep to one 

 species on a single trip from the hive, and even "as long as they can, before 

 going to another species" (Darwin, Fertilization of Plants, p. 415). This 

 constancy is considered most highly developed in the honeybee but is 

 claimed for certain Diptera (Bennett, Proc. Linn. Soc. Zool. XVII, p. 184). 

 Ord (1897, The constancy of the bee, Trans, nat. hist. soc. Glasgow, n. s., 

 V, Pt. 1, pp. 85-88) undertook to examine this as "one of the great pillars of 

 the Law of Natural Selection" and finds that "only about 30% have 

 proved inconstant while they were under my eye. ... In most cases 

 when I was able to follow the bee for any considerable time, I found that, 

 sooner or later, a change was made." He then records numerous observa- 

 tions which show inconstancy in a marked degree as from Leguminosae to 



