THE BEE-FLIES (BOMBYLIIDsE) IN THEIR 

 RELATIONS TO FLOWERS. 



By S. Graenicher. 



The Bombyliidtr represent highly specialized forms of the 

 dipterous type, insects that are of importance to many of our 

 flowers as regular and efficient pollen-distributors. Concerning 

 their relations to flowers in general, as also to certain types of 

 flowers, the results obtained from observations carried on in this 

 country are in some respects quite at variance with those reported 

 from European countries. 



In Knuth's Handbook of flower pollination, the most recent 

 and most important of its kind we meet in Vol. I, pp. 182 and 183 

 (Engl, translation) with the following statements: "Although 

 the family of the bee-flies ( Bombyliidce ) includes short tongued 

 forms (Loiiiatia, Anthrax, Argyromwba) with a decided prefer- 

 ence for flowers with exposed nectar, the species of Bombylius, 

 Systceclms and Disckistns are provided with a long proboscis, 

 with which they suck nectar as they hover.'" 



"On the other hand social flowers are much less convenient 

 for sucking while hovering, and are consecjuently only very rarely 

 visited by these insects." 



"Their preference for red, violet and blue is so remarkable 

 that they were observed on three times as many flowers of these 

 colors as on white or yellow ones. (Mueller, Alpenblumen 515)." 



In the foregoing three points are involved : First, the prefer- 

 ence of short-tongued species for flowers with exposed nectar ; 

 second, the relations to social flowers ; and third, the theory of 

 color preference as set forth by Herman Mueller. 



The following discussion is based on a comparison of observa- 

 tions made by the author in Milwaukee Co. with the very exten- 

 sive observations of Robertson 1 in Carlinville, Macoupin Co. in 

 southern Illinois. 



COLOR PREFERENCE. 



According to Mueller's theory, as referred to above, these 

 flies show a most decided preference for red, purple (or violet) 



1) Cited in Knuth's Handbuch d. Bluetenbiologie. Vol. III. part 2. pp. 

 374-376. 



01 • 



