192 The Plant World. 



"five species of Andrena fertilizing the flower, viz. A. nig- 

 roaenea K, A. fulvicus K, A. albicans K, A. siriceps 

 K, {A. irihialis K.) and A. pratensis Nyl . . These 



bees attracted by the color and perfume of the flower, fly into 

 the slipper-shaped lip, and bite the hairs lining its floor, which 

 are sometimes covered with small drops of honey. They try 

 for some time to escape by climbing up the vaulted sides of their 

 prison towards the orifice that they entered by; at last, after 

 creeping beneath the stigma, they manage with a great effort 

 to escape by one of the two small lateral openings at the base 

 of the lip; in doing so they smear one shoulder with a sticky 

 pollen from the anther immediately above. In the next flow- 

 er the bee, as it creeps up the stigma, leaves some pollen on its 

 papillae, which are long and point obliquely forw^ards, then 

 squeezing itself again through one of the small orifices it ac- 

 quires another load of pollen : cross-fertilization is thus eff'ected 

 regularly. ' ' 



Last summer I spent several hours in the habitat of the 

 royal moccasin flower watching the plants and their insect 

 guests. The only insects seen to visit the flowers were bees, and 

 they effected cross-fertilization for this species in exactly the 

 manner described by Miiller for C. calceolus. The bees were 

 captured in the act, and later identified as all belonging to the 

 genus Andrena. 



What good they obtained when visiting the flowers I have 

 not discovered. So far as I can detect, no nectar is secreted, 

 either inside the labellum, or within its tissues. Possibly the 

 hairs fringing the lining are eaten as Miiller observed. Darwin 

 speaking of the genus in general says, ' ' I have never been able 

 to detect nectar in the labellum, ' ' and Kurr makes the same 

 remark with respect to C. calceolus. 



Last year's stems persist bearing the seed pods, and attest 

 an intimate relation between plant and insect. The great num- 

 ber of seedling plants to be seen gives further evidence. In 

 order to get a more definite idea of the exact proportion of flow- 

 ers that are pollinated I made a careful count of blossoms and 

 last year's seed capsules. As the amount of bloom on each 

 plant is very constant from year to year, the comparison of the 

 seed of last year with the bloom of this year seems valid. The 

 following tables give the data obtained. 



