ARETHUSA 79 



Under the crimson-purple canopy the column is spread 

 out like a petal, and covers the anther, which in turn lies 

 directly over and projects beyond the stigma, in such a vs^ay 

 that the pollen could no more fall upon it than could a 

 sticky pop-corn ball fall and adhere to the under side of the 

 shelf it was lying on. The anther projects like a pointed hel- 

 met beyond the stigma, and remains tightly closed, holding 

 under it four little loose soft pellets of pollen, two in each cell. 

 The bee that creeps along the hairy channels that lead to the 

 nectar in the orchid's cup pries the pointed cap off as he is 

 backing out of the flower, and immediately it springs up on 

 a hinge and the pollen masses are caught in the hairs of his 

 head, and are soon deposited upon the stigma of another 

 flower as he creeps under it to get to the nectar. 



In Plate XXXIV., Fig. 2, the mechanism of this plan is 

 shown. In A the cap of the anther is closed, and as the bee 

 advances to thrust his tongue into the nectar sac, he seems to 

 press the edge of the anther inward and thus keep it even 

 more effectually closed. 



"As the bee retires, 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 in retiring 

 slides his back against the receptive viscid stigma, which 

 retains a portion of the pollen, and thus effects the cross 

 fertilisation. Professor Gray surmised that the pollen was 

 withdrawn on the insect's head, and it might be so withdrawn, 

 but in other allied orchids of the tribe Arethusa, in which 



