276 PROCEEDINGS OF THE ACADEMY OF [1888. 



seed. The flowers begin to expaud an liour before sun-down, assum- 

 ing a canipanulate form by dark. By sunrise the next morning 

 they are closed, and they remain closed till an hour before sun-i-et 

 when they again expand, and go through another day as 

 before. But at the third evening's expansion they become almost 

 rotate, closing again the next morning but only to wither and foil 

 away. The flower opens and fades within three days. 



During the first week or ten days of the flowering period, an 

 enormous amount of moisture exudes from every part of the flower. 

 It trickles down the outer surface of the [)erianths, collecting in 

 drops at the apices of the lobes, sometimes almost covering the leaves 

 with spots where the drops have fallen and indicating a somewhat 

 gummy character. The pistil is completely covered with minute 

 bullae, from which the same kind of liquid exudes. It is not a sweet 

 liquid, indeed differs from pure w^ater only in having a very slight 

 trace of bitterness. The moths become very active just after sun- 

 set, traveling up and down rapidly over the moistened stigma, 

 my idea being that they were feeding on the moisture, and that this 

 probability also included the case of the one noted a])ove as thrust-, 

 ing its proboscis down the tube of the stigma. But the insect's 

 motions are so rapid that in the twilight I could not feel absolutely 

 sure of the oljjects for which they were laboring so hard.^ 



The most interesting part of my observations comes in here. "When 

 about half the blossoms on the huge ])anicle had matured, the pro- 

 duction of moisture ceased. On the evening of the eighth of July I 

 tx)uld find no trace of an exudation of moisture, nor was there during 

 the whole remainder of the flowering period. Strange to say my 

 friends whose attention was called to this sudden cessation of a 

 watery overflow all suggested, "did you note an}' peculiar condition 

 of the atmosphere ?" I call attention to this here l)ecause it is so 

 common in reasoning on similar phenomena to say the atmosphere 

 was so-and-so therefore this or that resulted. It is the bane of 

 exact philosophical deductions that such hasty assumptions are com- 

 mon. We nuiy with more propriety remember that in trees and 

 plants generally a large amount of moisture is stored in the tissue 



' Tliis paper was read at the Cleveland meeting of the American Association 

 for the Advancement of Science, where Prof. Riley was present and it is due to 

 this eminent naturalist to say that he insisted on his former view that the sole ob- 

 ject of the insect in working down the pistil, was to ensure the fertilization of the 

 flower. 



