HABENARIA 6i 



flowers, this little fringed orchid is constructed on a principle 

 of reciprocity. The insects serve the plant and the plant 

 yields them food in return. Let us examine the structure, 

 which will be readily understood by reference to the dia- 

 grams. In this instance the bait consists of the usual sweet 

 secretion, here deposited at the end of a curved tubular 

 nectary, nearly an inch in length. The opening to this 

 nectary is seen directly in the heart of the flower. But 

 observe how that entrance is guarded — defended with two 

 clubs, if I may so speak, the pollen masses bearing some 

 such resemblance. These are hidden in two pockets, one 

 on each side of the opening. The lower extremity of each 

 is provided with a flat, sticky disc, turned inward. This is 

 all very simple. The trap is set. Now let us see how it 

 works. A small brown hawk-moth hovers near; he poises 

 like a humming-bird in front of the blossom, uncoils his 

 slender tongue and thrusts it into the opening of the nectary. 

 So transparent is this tiny tube that you can readily see, not 

 only the tongue within but the gradual absorption of the 

 nectar. As the moth thus sips he brings his tongue in 

 contact with one or both of the sticky discs. They clasp it 

 firmly and, as the member is withdrawn, they are pulled out 

 of their pockets (see Plate XXVI., Fig. 4). This alone is 

 surj)rising, but what follows is stranger still. In a very 

 few seconds the little club begins to sink forward, gradually 

 lowering, until it has brought itself nearly level with the 

 tongue. Wilted, you will imagine. Not so; it is still firm 

 in its new position. And what will be your surprise, if you 



