100 



the first to call attention to the fact that in some of our 

 Cypripediums a portion near the upper end of the inflated 

 sac in transparent, serving as a window. An insect would 

 naturally make for the light, and since this window is near 

 the small openmg the insect goes out. It gets some of the 

 pollen on its head as it comes in contact with the varnished 



FIG, 40. 

 Fig 40. 1, European lady's slipper {CypripeMum ealeeolus) ; on the left hand 

 side an insect, Andrena goin^ out of the flower with pollen adhering to its 

 back : 3, sectional side view of same ; S, an Andrena. (Kerner von M^trilaun) . 



film of the pollen. Some nectar is found on the hairs 

 in bottom of labellum. Now, when the insect flies to an- 

 other flower and enters by the large opening, it cannot fail 

 to get some of the pollen from its head, against the large 

 stigma which partially blocks the passage way. Dr. Gray- 

 says: "The stigma of every other orchid is smooth and 

 glutinous; this is merely moist and finely roughened; the 

 roughness comes from very minute projections all pointing 

 forward so that the surface may be likened to a wool-card 



