THE AMERICAN NATURALIST [Vol. XLIII 



a conspicuous object though much less so than before. 

 It was watched for a second ten minutes and received 

 only one visit, from a bumblebee (Bombus terricola). 

 During the first interval no visit was counted that the bee 

 did not enter the corolla and go down to the honey re- 

 ceptacle. "Within a few inches of this ''stump" and a 

 little lower down there was another squash flower, the 

 corolla of which had wilted and was nearly closed. Dur- 

 ing the second ten minutes this flower received five visits, 4 

 two from B. terricola and three from honey-bees, though 

 they were unable with a single exception to find an en- 

 trance. There can be little doubt that had the corolla 

 been present on the first flower these bees would have 

 entered it. 



On the fifteenth, the weather being favorable, the ex- 

 periments on the flowers of Cucurbita maxima were con- 

 tinued. Two flowers, both staminate, growing side by 

 side, their corollas touching, were selected. Number one 

 appeared rather older than number two, which had evi- 

 dently expanded very recently. Both were observed for 

 ten minutes. Number one received six visits, four from 

 Bombus terricola, two from the honey-bee; while number 

 two received thirteen visits, all from bumblebees (B. terri- 

 cola). The fresher condition of this flower probably 

 accounted for the larger number of visits. Both the calyx 

 lobes and the corolla were now cut away from number two, 

 the most attractive flower, leaving only the disc and the 

 monadelphous club of stamens. This was by no means 

 an inconspicuous object, as the yellowish disc is 15 mm. 

 in diameter, and the yellow anthers are over 2 cm. long. 

 The two flowers were watched for ten minutes. No visits 

 were made to number two; but number one received 

 twelve visits, six from honey-bees and six from B. terri- 

 cola. It is evident that the corolla was a great advantage, 

 and that number one suffered in competition with number 

 two, the number of visits to number one greatly increasing 

 when number two was rendered comparatively incon- 



* The bees alighted upon the corolla and tried to enter it. 



