40 ENTOMOLOGICAL NEWS [Feb., ? 2O 



rose flowering there at that time was Megapterium missouri- 

 ense. The flowers of this are yellow, 10-15 cm - wide; anthers 

 about 1.5 cm. long, the pollen grains large and so well joined 

 by cobwebby threads that they may be brushed off easily in 

 one mass. 



No exact time was obtained for either the first or last open- 

 ing of the flowers or visits of the bees, but the flowers seemed 

 to begin opening a little after sunset and many times bees 

 were seen flying about the flowers not yet opened. Most of 

 the flowers observed, opened in the earlier part of the evening. 

 The stigma is exserted some minutes before the flower opens 

 and the bees crawl about it searching for an opening in the 

 bud, so that ample opportunity for cross pollination is pro- 

 vided. In case of one flower, at least ten or twelve visits were 

 made before the flower opened; at one time three females 

 were on the bud, one attacking and driving away another. 

 They attempted to force their way into the apex and sides of 

 the bud, flying away after some seconds. In no case was 

 there any evidence of biting into the flower. 



As soon as a small opening appeared at the tip of the flower, 

 a bee would force her way in and begin collecting. Often 

 they forced only a partial entrance and then withdrew. The 

 flowers were quickly stripped of pollen so that after one or 

 two bees had collected at a flower, later visitors flew away 

 after a brief inspection. The pollen was gathered into a large 

 mass which seemed to be carried chiefly between the poster- 

 ior legs. On account of the darkness it was impossible to 

 follow the flight of the bees. The last visits were about an 

 hour after sunset (8:40 P. M. standard central time). 



The principal other evening primrose flowering at that 

 time in that locality was Hartmannia speciosa. The flowers 

 of this species are white, 5-10 cm. wide, otherwise similar to 

 those just described. They are not so strictly evening flower- 

 ing as they open earlier and remain open longer in the forenoon. 

 One trip was made to a place where these grew half a mile 

 from where the other notes were taken. At sundown many 

 of the flowers were open and their pollen undisturbed. Dur- 

 ing 15 or 20 minutes stay a single female was taken at the 

 flowers collecting pollen. 



