



PLATE 89. A. The fertilization of an orchid by a wasp. [After K.EKNEK.] 



i. Flowering spike of the broad-leaved hellebonne {Epipactys latifolia) upon which a wasp is 

 alighting. 2. Flower of the same seen from the front. 3. Side view of the same flower, with the 

 half of the perianth toward the observer cut away. 4. The two pollen masses joined by the sticky 

 rostellum. 5. The same flower being visited by a wasp which is licking honey and at the same 

 time detaching with its forehead the tip of the rostellum together with the pair of pollen masses. 

 6. The wasp leaving the flower with the pollen masses cemented to its head; the pollen stalks are 

 erect. 7. The wasp visiting another flower and pressing its forehead with the pollen masses (which 

 in the meantime have bent down) against the stigma. I, natural size ; the other figures, x 2. 



B. Fertilization of Salvia by a bumblebee. [After K.ERNER.] 



I. Part of an inflorescence of Salvia glutinosa ; the right-hand flower is being visited by a 

 bumblebee, and the pollen-covered anther is in the act of striking the insect's back. 2. Another 

 part of the same inflorescence with three open flowers in different stages of development; the left- 

 hand flowers are slightly more mature than the right-hand flower; one of the flowers is being 

 visited by a bumblebee which carries on its back pollen from a younger flower and is rubbing it 

 off on the deflexed stigma. 3. A single stamen, showing the hinge (h}. 4. A vertical section 

 through a blossom; the arrow indicates the direction through which bumblebees advance 

 toward the interior of the flower. 5. A similar section, showing how the anther is bent down- 

 ward by a bumblebee pushing against the bottom of the stamen. 



