678 



THE AMERICAN NATURALIST [Vol. XLV 



leaves. In this arrangement the yellow petal color still 

 remained perceptible to the visual powers of bees. 



At (b) the detached petals of a cotton blossom were 

 enclosed in a 250-c.c. graduated flask which was stoppered 

 and fastened among the cotton leaves. The yellow petals 

 were plainly visible through the clear thin glass of the 

 flask. 



At (c) a normal cotton blossom as a control. 



(a) Eeceived no inspections. 



(b) Eeceived one inspection by a honey bee which 

 touched the flask. 



(c) Received three inspections by honey bees. Two 

 bees did not enter the blossom but alighted outside to 

 get at the extra-involucral nectaries. During this experi- 

 ment the bees were too infrequent visitors to make any 

 results conclusive. 



Experiment No. 34— August 12. Time of observa- 

 tions 45 minutes, from 1 :30 to 2 :15 p.m. This experiment 

 was an exact duplicate of the previous one. 



(a) Petals of cotton blossom on a leaf between glass 

 plates as at (a) in Experiment 33. 



(b) Petals of cotton blossoms enclosed in a flask as at 

 (b) in Experiment 33. 



(c) Normal blossoms growing in situ as a control. 

 The blossom at (a) was twice inspected by Melissodes. 



The petals in the flask at (b) were inspected two times by 

 bees, once by a honey bee and once by a small, unidenti- 

 fied bee. The blossom at (c) was inspected six times, in- 

 cluding five entrances. One inspection was made by a 

 small, unidentified bee, four entrances were by honey 

 bees, and one entrance by a Melissodes. 



For several days it was rather difficult to secure sat- 

 isfactory data, as the bees were much less frequent visit- 

 ors. The species of Melissodes, which were extremely 

 common at the beginning of the experiments finally be- 

 came far less common, although honey bees greatly 

 increased. It is very interesting to note that many honey 

 bees finally began to confine their visits solely to the 

 outer involucral nectaries instead of entering the bios- 



