208 



ENTOMOLOGY 



are predaceous or parasitic upon the others. In the Iris, according to 

 Needham, two small bees (Clisodon terminalis and Osmia distincta) are 

 the most important pollenizers, and next to them a few syrphid flies, 

 while bumble bees also are of some importance. The beetle Trichius 

 piger and several small flies obtain pollen without assisting the plant, 

 and Pamphila, Eudamus, Chrysophanus and some other butterflies 

 succeed after many trials in stealing the nectar from the outside (Fig. 261). 

 A weevil (Mononychus vulpeculus) punctures the nectary, and the flowing 



FIG. 261. A butterfly, Polites peck i us, stealing nectar from a flower of Iris versicolor. 



reduced. 



Slightly 



nectar then attracts a great variety of insects. Grasshoppers and cater- 

 pillars eat the flowers, an ortalid fly destroys the buds, and several par- 

 asitic or predaceous insects haunt the plant; in all, over sixty species of 

 insects are concerned in one way or another with the Iris. 



Modifications of Insects with Reference to Flowers. While 

 the manifold and exquisite adaptations of the flower for cross pollination 

 have engaged universal attention, very little has been recorded concern- 

 ing the adaptations of insects in relation to flowers. In fact, the adapta- 

 tion is largely one-sided; flowers have become adjusted to the structure 



