SOME REMARKABLE ADAPTATIONS OF PLANTS TO INSECTS. 101 



self-fertilisation is out of the question. There must be a common cause 

 for all these minute adaptations taken together, and there is none more 

 theoretically appropriate than the insect itself. 



As a second instance, taken this time from the family of Orchids, 

 * Coryanthcs macrantha affords another example of curious adaptations in 



all parts of the flower for securing the transference of pollen to the stigma. 

 The labellum is so modified as to form a large bowl, suspended by the 

 thickened curved base which is very strong, being provided with ridges 

 containing a sweet juice, which is attractive to a largo kind of 

 humble-bee. (Fig. 19.) 



The " gynostemium,"* or column, hangs vertically downwards, against 

 the truncated end of which the front edge of the bowl is closely pressed, 

 the strong and bent stem of the labellum forming a sort of spring which 



Fig 18. — A Bee being dusted with Pollen in the Blossosi 

 OF A Salvia.! 



forces the bowl upwards against it. Two little horns are borne by the 

 gynostemium, and secrete water, which drips into the bowl, keeping the 

 base covered with it, the superfluity escaping from two lateral depressions 

 in front. 



As soon as a flower is expanded bees arrive in great numbers. One is 

 soon pushed into the bowl, and having its wings wetted does not attempt 

 to fly upwards, but escapes by crawling out between the front edge of the 

 bowl and the blunt end of the column. In so doing it carries oft' the two 

 free pollen-masses, which project just over the edge in front. A continuous 

 stream of bees has been observed forcing their way one after another all 

 day ! In order to convey the pollen to the stigma, which lies at the back of 



* The column formed by style and filament combined. 



t Copied from Konrad Sprengel's Das neu entdeckte Geheimniss der Natur in Bait 

 und Befruchtung der Blumen (1793). 



