Chap. L ORCHIS, 15 



flowers almost always have both poUinia remoyed, 

 whilst the younger flowers close beneath the buds, 

 which will have been seldomer visited, have frequently 

 only one poUinium removed. In a spike of Orchis 

 macidata, I found as many as ten flowers, chiefly the 

 upper ones, ^\ hich had only one pollinium removed ; 

 the other pollinium being still in its proper place with 

 the lip of the rostellum well closed up ; so that all the 

 mechanism was perfect for its subsequent removal by 

 gome other insect. 



When the first edition of this book was published, 

 I had not seen any insects visiting the flowers of 

 the present species ; but a friend watched some plants, 

 •^nd saw them visited by several humble-bees, appa- 

 rently Bomhus muscorum ; and Dr. H. Miiller * has seen 

 four other species of Bombus at work. He caught 

 ninety-seven specimens, and of these thirty-two had 

 pollinia attached to their heads. 



The description now given of the action of the 

 organs in Orchis mascula applies to 0, morio, fusca, 

 macvlata, and latifdia. These species present slight 

 and apparently co-ordinated differences in the length 

 of their caudicles, in the direction of the nectary, 

 in the shape and position of the stigma, but they 

 are not worth detailing. In all, the pollinia when 

 removed from the anther-cells undergo the curious 

 movement of depression, which is so necessary to 

 place them in a right position on an insect's head 

 for striking the stigmatic surface of another flower. 

 Six species of humble-bees, the hive-bee and two 

 other kinds have been seen by H. Miiller and myself 

 risitiug the flowers of Orchis morio. On some of the 



* ' Die Befruchtung, &c., p. 84. 



