19 



hungry and rest when tired. On the other hand, bees are 

 always bustling about; they have many babies at home to 

 feed and can stop work neither to play nor rest. 



Investigation will show, too, that bees are very constant 

 in their work. Although they feed upon many kinds of 

 flowers, they do not mix their foods; if they are visiting 

 clover, they continue to visit it, passing by any other spe- 

 cies that may intervene. It seems almost as though they 

 must realize that they should not leave clover pollen at the 

 door of self-heal or any other different species of flower. 

 Not that it would do any damage, for nearly all flowers 

 are infertile to pollen from any other species, but it would 

 be a useless waste of precious pollen. 



Bombus finds the latchstring out at many flowers that are 

 permanently closed to most insect visitors. For instance 

 her weight is just sufficient, when hanging on the lower lip 

 of toadflax or "butter-and-eggs" to open its pouting mouth 

 so she can insert her tongue and drain its nectary. Smaller 

 bees and, sometimes, ants finding that the large orange 

 palate blocks access to the honey by legitimate channels, 

 often gnaw through the spur and steal it from without. 

 Another excellent example of a flower closed to plebian in- 

 sects is that of closed gentian. The five parts of its corolla 

 come together so closely at the top that, try as they will, 

 ant, fly or small bee cannot force it open, but they do some- 

 times gnaw through the outside. Bombus, however, by 

 using the great strength in her legs and her tongue grad- 

 ually forces the petals apart so she can squeeze her head 

 and perhaps three-quarters of her body inside the tube, 

 from which position she can get at the abundant supply of 

 nectar at the bottom. 



Probably the orchids offer the most interesting studies in 

 plant fertilization. Concrete examples of how bees and 

 moths pollenize some of these will be found in another 

 chapter about orchids. 



