PLATE 17 



Listera ovata R. Br. Twaybkde. Complete plant from Challes-les-Eaux, 

 France, May 7th, 1928. 



1. Side view, ovary, colxmin and Up. 



2. Front view of complete flower. 



■2. a. Base of lip and column after removal of pollinia. 



3. Eucera longicornis L. 



4. Empis tesselata F. 



Figs. 1-4 enlarged, a. anther; r. rostellum; h. hood of column. 



