OF NATURAL SELECTION. 83 



and that certain insects depended in main part on its 

 nectar for food. I could give many facts showing how- 

 anxious bees are to save time : for instance, their habit of 

 cutting holes and sucking the nectar at the luses of certain 

 flowers, which with a very little more trouble they can enter 

 by the mouth. Bearing such facts in mind, it may be be- 

 lieved that under certain circumstances individual differences 

 in the curvature or length of the proboscis, etc., coo slight to 

 be appreciated by us, might profit a bee or o'oher insect, so 

 that certain individuals would be able to obtain their food 

 more quickly than others ; and thus the communities to 

 which they belonged would flourish and tnK>w off many 

 swarms inheriting the same peculiarities. Xne tubes of the 

 corolla of the common red or incarnate clovers (Tri folium 

 pratense and incarnatum) do not on a hasty glance appear 

 to differ in length ; yet the hive-bee can easily suck the 

 nectar out of the incarnate clover, but not out of the common 

 red clover, which is visited by humble-bees alone, so that 

 whole fields of the red clover offer in vain an abundant 

 supply of precious nectar to the hive-bee. That this nectar 

 is much liked by the hive-bee is certain ; for I have repeat- 

 edly seen, but only in the autumn, many hive-bees sucking 

 the flowers through holes .bitten in the base of the tube by 

 humble-bees. The difference in the length of the corolla 

 in the two kinds of clover, which determines the visits of 

 the hive-bee, must be very trifling ; for I have been assured 

 that when red clover has been mown, the flowers of the 

 second crop are somewhat smaller, and that these are visited 

 by many hive-bees. I do not know whether this statement 

 is accurate ; nor whether another published statement can 

 be trusted, namely, that the Ligurian bee, which is generally 

 considered a mere variety of the common hive-bee, and which 

 freely crosses with it, is able to reach and suck the nectar 

 of the red clover. Thus, in a country where this kind of 

 clover abounded, it might be a great advantage to the hive- 

 bee to have a slightly longer or differently constructed pro- 

 boscis. On the other hand, as the fertility of this clover 

 absolutely depends on bees visiting the flowers, if humble- 

 bees were to become rare in any country, it might be a great 

 advantage to the plant to have a shorter or more deeply 

 divided corolla, so that the hive-bees should be enabled to 

 suck its flowers. Thus I can understand how a flower and 

 a bee might slowly become, either simultaneously or one 

 after the other, modified and adapted to each other in the 



