268 



ENTOMOLOGY 



FIG. 261, 



is noteworthy that pollination is performed only by the more 

 highly organized insects, the bees heading the list. 



Of all the insects that haunt the same flower, it frequently 

 happens that only a few are of any use to the flower itself; 

 many come for pollen only; many secure the nectar illegiti- 

 mately ; thus bumble bees puncture the nectaries of columbine, 

 snapdragon and trumpet creeper from the outside, and wasps 

 of the genus Odynerus cut through the corolla of Pentstemon 

 lavigatiis, making a hole opposite each nectary ; then there are 

 the many insects that devour the floral organs, and the insects 

 which are predaceous or parasitic upon the others. In the 

 Iris, according to Needham, two small bees (Clisodon termi- 

 nalis and Osmia' distinct a) are the most important pollenizers, 

 and next to them a few syrphid flies, while bumble bees also 



are of some impor- 

 tance. The beetle 

 Trichius pigcr and sev- 

 eral small flies obtain 

 pollen without assist- 

 ing the plant, and 

 Pamphila, Eudamus, 

 Chrysophanus a n d 

 some other butterflies 

 succeed after many 

 trials in stealing the 

 nectar from the out- 

 side (Fig. 260). A 

 weevil (Mononychus 

 vulpcculus) punctures 

 the nectary, and the 

 flowing nectar then at- 

 tracts a great variety of 

 insects. Grasshoppers 

 and caterpillars eat the 

 flowers, an ortalid fly destroys the buds, and several parasitic 

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

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



A, right mandible; B, right maxilla; C, hypo- 

 pharynx, of a pollen-eating beetle, Euphoria inda. 

 Enlarged. (The mandibles are remarkable in 

 being two-lobed.) 



