56 PROCEEDINGS OF THE ACADEMY OF [1894. 



are tlie cases on tlie other side, aud this cleistogamoiis case is one. 

 But ill the normal flowers only a few insects could work to advantage. 

 The spur of the nectary is incurved, and only creatures with a long 

 and flexible tongue could reach the sweet deposits stored, mostly, at 

 the base of the tube. In my "Flowers aud Ferns of the United 

 States" (Series II, p. 44, 1880) Prof. W. W. Bailey is quoted on 

 the authority of a friend of his that "the sacs were all perforated by 

 bumble bees." Numerous species have their sacs perforated in 

 this way, and all have been charged, even by myself, to bumble 

 bees. Dr. J. H. Schueck of Mount Carmel, Illinois, suggested to 

 me that this is probably a mistake, and that species of Xylocopa 

 (carpenter-bees) and not Bombiis, are responsible for this act. 

 Watching these flowers I found the slits were made by a wasp, Vespa 

 maculata, that some species of Xylocopa, and also the honey bee, 

 took advantage of the work of the wasp; but the only species of 

 l)umble bee I noticed W'orking on the flowers, Bombiis Pennsylvani- 

 cns, entered the flower every time by the flower's mouth, and got 

 the nectar from the curved spurs as best it could. Properly speak- 

 ing, the openings made by the hornet are not slits, but rough openings, 

 chewed out. The slits proper appeared to have been made by the 

 small carpenter bees. It is evident that in view of the many insects 

 these flowers support, no advantage is received by the flowers in 

 return. 



The relation of Bomhus to fertilization was next examined. 

 The longitudinal streak of white pollen on the back of the visiting- 

 bee gave it a picturesque appearance. That he could carry pollen 

 from one flower to the other was very apparent. It seems impossible 

 for the visiting bee to reach the stigma, as these are protected by con- 

 uivent scales under the anthers, which form a close cap covering the 

 stigma. Usually the earlier petaliferous flowers are infertile. In 

 these plants, early in August, numerous flowers had perfected fruit, 

 though the great majority were infertile. In what manner did the 

 bee or the humming bird aid in the pollination? Examining a num- 

 ber of flowers after these creatures had retired I was satisfied that 

 they did not aid in any way. I have had evidence in other cases 

 that where sufficient moisture exists, pollen tubes can reach the 

 stigma without actual contact witli it. There is abundant niois^ture 

 around the stigma, and it is not improbable that the pollen tubes, 

 by the aid of this moisture, pass over the membranous border, in 



