1888.] NATURAL SCIENCES OF PHILADELPHIA. 275 



small insects, drone bees, and other creatures live in indolence by 

 the sweat of other brows. Tliere are nian}^ parallels between plants 

 and animals. Is Yucca to be a case of absolute servitude on the 

 part of the insect, from sheer indolence on the part of the Yucca to 

 do its own work? It seems to me we shall not be able to draw the 

 veil from this great mystery till we make continuous and careful 

 observations of all the facts in its history, and place them on record 

 for comparison with those which others maj'^ make. 



Prof. Riley once made the remarkable statement that he had seen 

 the Yucca Moth collect pollen, and thrust it down the tube of the 

 stigma, as if it knew that some such process was necessary to insure 

 fertilization. Dr. En2:elmann had found in the Yuccas he examined, 

 that the apex of the pistil was not stigmatic, — the receptive portion 

 was low down in the tube. The two observations, taken together, 

 gave color to the supposed object of the insect. I have shown, (see 

 Proceedings of the Meetings at Cincinnatti, Saratoga and Buffalo,) 

 that pollen applied to the apex in Y. angustifolia, and protected by 

 gauze from the insect, resulted in seed just as well as Avhen the work 

 .was done by an insect. The tubular character noted by Dr. Engel- 

 mann cannot therefore be a constant one; and we shall have to 

 admit that the reasoning of the insect which led it to thrust the 

 pollen down the tube in the other species, leads it to perceive there 

 is no tul)e in Y. angustifolia, and that the application of pollen to 

 the bare apex is sufficient in this species. 



Up to this season I had never been able to detect the insect be- 

 have in the plants around my house, as Professor Riley saw them 

 behave; but I have always conceded that he is too careful and too 

 close an observer to have been mistaken in such an observation. 

 The record of the act of the insect thrusting its tongue down the 

 stigmatic tube, from so accurate a naturalist, needs no confirma- 

 tion from any one, however one may be allowed to hold his judgment 

 in suspense as to the object of the insect in such behavior ; not then 

 as confirming Prof. Riley, but as part of my observations of this year, I 

 desire to say that I have recently seen an insect at the same task. It 

 worked its proboscis up and down the tube of the pistil, much as a 

 sportsman would load his gun. 



I find, in this region Yucca filamentosa commenced to bloom this 

 year about the end of June. Some plants will bloom a full week, or 

 occasionally ten days before others, though years ago, all the plants 

 under my notice came from root cuttings of one stock and not from 



