H8Q 



THE AMERICAN NATURALIST [Vol. XLV 



sodes. 130 or 7.8 per cent, were by honey bees. 40 or 

 2.4 per cent, were by bumble bees. 83 or 5 per cent, were 

 by various unidentified bees. 



Eleven visits were made by Ells plum I pes and one 

 by a large butterfly. The size and yellow color of the 

 petals serve to make cotton blossoms particularly con- 

 spicuous in contrast with their shaded background of 

 dark green foliage. Once visiting insects have entered 

 a cotton field, there is little doubt but that their visual 

 powers almost wholly enable them to discover the 

 blossoms. This is indicated by those experiments where 

 the corolla of certain blossoms lias been covered or 

 entirely removed, since following this procedure the re- 

 maining portions of the blossoms were unvisited. The 

 size and general appearance of cotton blossoms do not 

 appear to be of great importance in initiating the process 

 of inspection, since a single petal may receive as many 

 inspections as the control. It is of interest to note in this 

 connection that in experiments 14 and 15 the bees did not 

 discriminate between the white convolvulus and cotton 

 blossoms at least until after closer inspection. When 

 such artificial material as cloth or paper was used, al- 

 though the color more or less resembled cotton petals, 

 the bees were rarely induced to inspect it closely. This 

 discrimination may depend upon perceptible differences 

 in color and texture rather than the presence of repellent 

 odors which the material possessed. Many eminent 

 observers have adduced a great deal of evidence which 

 proves beyond doubt that bees develop keen powers of 

 discernment in their associations with the structural 

 details of different flowers. 



The actual number of entrances into cotton blossoms 

 is small in comparison with those instances when 

 blossoms have been merely perceived or inspected. The 

 writer's observations show that of 1,061 inspections of 

 the control blossoms only 129, or 12.1 per cent., were 

 actual entrances. One hundred and twenty of these en- 

 trances were distributed among the several kinds of 

 bees, as follows : 45, or 37.5 per cent., were by Melissodes; 



