CHAPTER VII 

 BEES WHICH VISIT ONLY ONE KIND OF FLOWER 



ONE warm afternoon on the 20th of July I was collect- 

 ing insects from a boat on the Medomac River. A 

 thunder-shower was coming up in the northwest. The 

 air was very still and in that peculiar condition which pre- 

 cedes an electric storm. At such times insects are very sluggish 

 and seek shelter against the approaching tempest. The silence 

 was broken only by the rumbling peals of the distant thunder, 

 following the bright flashes of lightning, which illumined the 

 dark thunder-heads of the advancing clouds. It became 

 necessary for me to hasten homeward. To my surprise I 

 noticed on almost every one of the violet-blue spikes of the 

 pickerel-weed {Pontederia cordata), a species of water-hyacinth, 

 which in countless numbers fringed the winding stream on 

 both sides, one to several small bees. They had crept within 

 the bilabiate flowers as far as possible, and were evidently in- 

 tending to await there the passing of the storm. They were so 

 inactive that no net was required, and I could easily knock 

 them off into the cyanide jar. I collected about 40 specimens 

 and could have easily collected hundreds. This phenomenon 

 has never been repeated to my knowledge. 



On examination the bee proved to be Halictoides novce-anglioBy 

 or the pickerel-weed bee. Every season when the pickerel- 

 weed is in bloom I find both sexes of this bee on its flowers, 

 and although I have carefully observed the visitors to many 

 other plants in this locality, I have never met with it elsewhere. 

 Apparently in this region it never visits any other flower — it 



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