No. 439 ] NORTHERN GAMOPETALOUS FLOWERS. 477 



German and Swiss flora of a blue color being produced by the 

 selective agency of Lepidoptera." That butterflies visit very 

 frequently flowers of a great variety of colors is well known to 

 every observer. Of 1432 visits made by 100 species of Rhopalo- 

 cera, 44.87; were made to greenish-yellow, yellow and white 

 flowers; and 55.2% to red, violet, and blue flowers. 1 The per- 

 centage of visits to wasp and bee flowers was 16.7%, and to 

 lepidopterous flowers 13.8% ; but the greatest number of visits 

 was to flowers of the type of the Composite which was 43.2', . 

 The percentage of visits to flowers with the honey exposed or 

 not deeply concealed was small. Essentially the same results 

 were reached by the comparison of 2086 visits of 220 Lepidop- 

 tera. The above figures show that butterflies are influenced 

 more by the form of the flower than by its color. Red and blue 

 flowers are usually tubular and contain more honey than yellow 

 and white flowers, which are more often rotate and exposed to 

 pillagers of every sort. The flat, capitate inflorescence of the 

 Composite is especially well adapted to butterflies. It is also 

 noteworthy that in the families and genera, which contain red- 

 colored butterfly flowers, blue is very rare or wholly absent. 

 The evidence that red floral coloration is a source of pleasure to 



