ACONITUM COLUMBIANUM. 21 



10 each were made to blue and purple, 4 to red, 3 each to green and orange- 

 red, and 2 to yellow. 



Both the inside and outside of 10 perianths were painted with each of 

 the following colors: red, blue, yellow, green, purple, and 10 normal flowers 

 were used for comparison. The following short record shows the resulting 

 behavior, each line indicating a different visitor: 



Bombus juxtus, 6 normal, low over blue, and then flew away, 

 normal, low over blue, and then flew away. 

 2 normal, blue, 2 normal, blue, normal, 

 normal, blue, normal, blue, normal, 

 normal, normal, 

 blue, normal. 



ADDITION OF HONEY AND ODOR. 



Honey. — In order to throw light on the role of nectar in attraction, 

 four kinds of sweets were used, viz., honey, diluted honey, diluted white 

 Karo sirup, and beet-sugar solution. These were put on the side petals of 

 some flowers, on the stamens and styles of others, and in the nectary opening 

 of still others. In some cases, Bombus juxtus went directly to the nectary 

 of flowers with honey at the sides of the petals, sipped as usual, and flew away 

 without discovering the honey. In other cases, it flew down to these flowers, 

 almost landed, and then flew away as if frightened, perhaps by the unusual 

 appearance. When the various sugar solutions were put into the nectary 

 openings, Bombus took nectar as usual, but stayed longer at each flower, owing 

 to the increased supply. When Karo sirup or sugar solution was put on the 

 stamens, B. juxtus and bifarius did not notice it in some cases, for they went 

 past to the nectary and then flew away. Other individuals of B. juxtus 

 landed in such a way that the mouth-parts accidentally touched the sirup. 

 After taking sirup from such a flower a bee flew to a normal one, pushed its 

 ligule around the stamens as if looking for more sirup, then advanced to the 

 nectary opening, and obtained nectar as usual. In the next flower, where 

 the stamens were covered with honey, it proceeded to take this supply and 

 fly away without trying for nectar. 



The procedure of Bombus juxtus was various in the flowers where the honey 

 drop was placed on the stamen group. One bee landed without noticing 

 the honey on the anthers, but pushed its head into the hood and took nectar. 

 Another alighted in such a way that its head touched the honey. It 

 obtained honey in 3 flowers of this type, without paying any attention to the 

 nectary. A third did not notice the honey drop, but secured nectar in the 

 usual manner. As it started to fly away its thorax stuck to the anthers, 

 and it scraped the honey from its front legs, without even discovering that 

 it was sweet or edible. B. bifarius went in succession to 6 flowers with drops 

 of honey on the anthers; it did not notice the honey, but took nectar as usual. 

 B. juxtus landed on the lower sepal of a flower in such a way that its head 

 touched the honey on the anthers, and it sipped until the drop was all gone. 

 Instead of pushing its ligule into the nectary, it flew to the next flower, 

 where a drop of honey was in the same position, and proceeded to suck all 

 of it. When it started to fly away, its tongue stuck in the honey and it had 

 a difficult time to free itself. 



