98 NEOTTE.E. CiiAK IV. 



Nevertheless the pollen-masses were not removed 

 nearly so cleanly as those which had been naturally 

 removed by insects. I tried dozens of flowers, always 

 with the same imperfect result. It then occurred to 

 me, tliat an insect in backing out of the flower would 

 naturally push with some part of its body against the 

 blunt and projecting upper end of the anther, which 

 overhangs the stigmatic surface. Accordingly I so 

 held a brush that, whilst brushing upwards against the 

 rostellum, I pushed against the blunt solid end of the 

 anther (see flg. C) ; this at once eased the pollinia, and 

 they were withdrawn in an entire state. At last I 

 understood the mechanism of the flower. 



The large anther stands above and behind the 

 stigma, forming an angle with it (fig. C), so that the 

 pollinia when withdrawn by an insect would adhere 

 to its head or body in a position fitted to strike the 

 sloping stigmatic surface as soon as another flower 

 was visited. Hence we have not here, or in any of 

 the Neottese, that movement of depression so common 

 with the pollinia of the Ophreae. When an insect 

 with the pollinia attached to its back or head enters 

 another flower, the easy depression of the distal portion 

 of the labellum probably plays an important part ; for 

 the pollen-masses are extremely friable, and if they 

 were struck against the tips of the petals much of the 

 pollen would be lost ; but as it is, an open gangway 

 is offered, and the viscid stigma, with its lower pro- 

 tuberant part lying in front, is the first object against 

 which the pollen -masses projecting forwards from the 

 insect's head or back would naturally strike. I may 

 add that in one large lot of flower-spikes, a great 

 majority of the pollinia had been naturally and 

 cleanly removed. 



In order to ascertain m hether I was right in believing 



