blossom Hosts and Insect Guests 



sipping, its head must pass beyond the anther well 

 into the opening of the flower. Its body must be i 

 sufficiently large to come in contact with the anther. 

 Such requisites are perfectly fulfilled by the bum- 

 blebee, and we may well hazard the prophecy 

 that the Bombus is the welcomed affinity of the 

 flower. 



The diagrams (Fig. i) sufficiently illustrate the 



Fig. 



efficacy of the beautiful plan involved. At A the 

 bee is seen sipping the nectar. His forward move- 

 ment thus far to this point has only seemed to 

 press the edge of the anther inward, and thus keep 

 it even more effectually closed. As the bee retires 

 (B), the backward motion opens the lid, and the 

 sticky pollen is thus brought against the insect's 

 back, where it adheres in a solid mass. He now flies 

 to the next Arethusa blossom, enters it as before, and 



154 



