22 OUR NATIVE ORCHIDS 



" The pollen discs are here very close together, and are 

 protected within a membranous cup; in which they sit as 

 in a socket. As the insect inserts his head at the opening 

 (Plate IX., Fig. 2) it is brought against this tender membrane, 

 which ruptures and exposes the viscid glands of the pollen 

 masses. These become instantly attached to the face or 

 head, and perhaps to the eyes of the burly visitor. As the 

 insect retreats from the flower, one or both of the pollinia 

 are withdrawn, as at Plate IX., Fig. 3. Then follows a 

 downward movement, which exactly anticipates the position 

 of the stigma, and as the bee enters the next flower the pollen 

 clubs are forced against it. 



" In the case of a smaller bee visiting the flower, the insect 

 would find it necessary to creep further into the opening, and 

 thus might bring its thorax against the pollen glands. In 

 either case the change of position in the pollinia would insure 

 the same result. 



" We have thus seen adaptation to the thorax, the eyes 

 and the face in the examples given. And the entrance of 

 the flower in each instance is so formed as to insure the 

 proper angle of approach for the insect for the accom- 

 plishment of the desired result. This direct approach, 

 so necessary in many orchids, is insured by various 

 devices — by the position of the lip upon which the 

 insect must alight; by the narrow entrance of the 

 throat of the flower in front of the nectary; and by a 

 fissure in the centre of the lip, by which the tongue is 

 conducted." 



