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aloue were open. TTpoii approachiug- this plant I saw a Pronuba enter 

 one of the opened flowers and take up a ])o.sition on one side of the 

 ovary, her head being directed toward but not quite reaching the 

 stigma. She now [)ressed the top of her body against the ovary in 

 the bottom of the groove over which she was standing, and appeared 

 to be inserting her ovipositor into the tender ovary. She remained in 

 this position for fully ten minutes, then she walked up the ovary and 

 style until her head was slightly above the upper surface of the stigma, 

 after which she stretched out her maxillary tentacles and repeatedly 

 pressed their tips into the upper surface of the stigma, moving her head 

 back and forth as she did so. Previous to this the tentacles had been 

 held resting against a mass of pollen nearly half the size of her head, 

 which was attached to the under side of her head. The process of thus 

 pollinating the pistil lasted about half a minute, after which she de- 

 scended the ovary and at once mounted to the top of one of the stamens 

 until her head was slightly above the anthers or pollen-masses; then 

 with her tentacles she removed both pollen-masses, moving her head 

 from side to side during the operation, and added the pollen thus gath- 

 ered to the mass already attached to the under side of her head. Next 

 she ascended two of the other stamens in succession and in a similar 

 manner removed a single pollen-mass from each of them, then took uj) a 

 position on one side of the ovary and rested from her labors. 



It was indeed surprising to witness the evident intelligence which 

 this insect displayed in all her actions whereby the pistil of the flower 

 became pollinated solely through her own labors. That she went 

 through these maneuvers with the evident intention of pollinating the 

 flower appears to admit of no doubt. She evidently did not gather 

 the pollen to serve as food for herself. The small quantity of food which 

 she requires during the few weeks of her existence could easily betaken 

 direct from the stamens if she required pollen for food, l^or could the 

 operation of pressing the tips of her pollen-besmeared tentacles into 

 the stigma have any connection whatever with the'taking of food, since 

 these organs are no better fitted for taking u]) liquid food than her feet 

 are, and the proboscis was not brought into use during this operation. 

 The entire operation detailed above was evidently ])erformed for the 

 express purpose of providing food for her offspring which were to live 

 in the seed-pods; and there also appears to be no doubt that she was 

 in possession of the fact that unless she did thus pollinate the flower, 

 there would be no seed-pods for her offspring to live in. 



Wishing to ascertain if any other agency besides the Pronuba could 

 effect the pollinating of the flower of Yucca whipplei, I inclosed the 

 flower-bearing portion of five of these plants in thin muslin sacks on 

 the 12th of June of the present year; none of the flowers on any of 

 these plants had yet even partially opened, and I carefully removed all 

 the insects from these jdants before putting on the sacks. On the 24th 

 of the following July I removed the sacks of two of these plants; one 



