36 



NORMAL AND EXPERIMENTAL POLLINATION. 



pended from the branches to increase the number of normal flowers under 

 observation. One Halictus pulzenus went to all flowers, making no dis- 

 tinction between the normal and those with artificial corollas. Another 

 individual visited one yellow, two green, and many normal flowers. Bombus 

 proximus went to 118 normal flowers and only 18 with crepe corollas, 

 Syrphus americanus to 3 yellow, 2 green, and 11 normal, and Clisodon 

 terminalis to 18 normal and 1 white crepe flower. 



The results of observations made on another day are given in table 17, 

 which shows the visits to normal and crepe flowers during an hour. Eight 

 natural flowers were used, together with 4 of each color, making 20 artificial 

 flowers in all. 



Later, Bombus proximus and juxtus visited these bushes several times, 

 but stopped only at the natural flowers, passing by the artificial corollas. 

 The first stopped twice at a petal lying on some leaves and examined it, 

 but did not land at any of the artificial flowers in passing from one natural 

 flower to others more distant. 



ADDITION OF HONEY AND ODOR. 



Honey. — Diluted honey was placed in the center of the stamen group, 

 so that visitors coming for either pollen or nectar would be sure to come in 

 contact with it. This glistened in the sunlight and was distinctly visible 

 3 meters away from the flowers. In general, Bombus proximus avoided 

 flowers treated in this way, and when it did land usually paid no attention 

 to the honey. When this was noticed, the bee flew away suddenly, or 

 avoided it and trampled among the anthers on the other side of the flower. 

 One individual landed at a flower with diluted honey, commenced at once 

 to sip nectar, and stayed for a long time. It flew away for a second, came 

 back again, and took more nectar. This bee went to the next flower which 

 was normal and trampled among the stamens in the usual fashion. No 

 pollen was collected in the next two flowers with honey- drops, but the bee 

 secured nectar. Three normal flowers were then visited in succession and 

 at each it trampled among the stamens and collected pollen. Monumetha 

 albifrons sipped honey for 60 seconds on a flower that had pure honey-drops 

 on the stamens. It also went to those in which the honey-drops were 

 diluted, but showed no preference for either kind. 



Twenty flowers of each kind were used in the following experiment to 

 find out whether honey would prove an added attraction to visitors; the 

 period of observation was an hour. 



