214 MISSOURI BOTANICAL GARDEN. 



Having withdrawn the oviduct, in doing which she moves 

 up so that her head is about level with the stigma, or even 

 before this organ is entirely freed, the moth usually pro- 

 ceeds to pollination ; but it is not infrequent for two eggs 

 to be laid between each two visits to the stigma, and, owing 

 to her peculiar alertness, she appears to be even more easily 

 frightened into omitting pollination than are the other 

 species of Pronuba. Standing with her head at about the 

 height of the stigma, with the short tongue projecting out 

 in front, she uncoils her long tentacles from the compact 

 mass of pollinia, which she carries similarly to the 

 other Pronubas, only that small part of her burden which 

 adheres to the bases of the tentacles being removed from it, 

 and, raising her body on tiptoe, she very slowly saws the 

 tentacles back and forth across the top of the stigma, gen- 

 erally following one of the three shallow grooves, and very 

 carefully working their slender tips into the more or less 

 gummy exudation over the central depression. Sometimes 

 the operation is interrupted long enough to admit of the 

 tentacles being coiled back against the load of pollen and 

 again extended ; but the curious manner in which her head 

 is held back from the stigma as a rule prevents any of the 

 main load from reaching even the marginal papillae. 



On first witnessing this operation, I was impressed by 

 the much slower motion of the moth than usual, and the 

 evident care which she took to run the ends of the tentacles 

 into the central depression of the stigma, which I then sup- 

 posed to be solid ; the subsequent discovery of the stylar 

 canal, communicating with the ovarian cells, showed that 

 it is into this narrow passage that she so carefully guides 

 the tips of her tentacles with their modicum of pollen, and 

 no doubt the abundant stigmatic secretion serves not only 

 to foster the development of the nascent pollen tubes after 

 pollination, but, wetting the tentacles, aids in the disinte- 

 gration of her mass of pollinia. These, if really related to 

 her work, would seem to have acquired their coherent 

 structure as a means of facilitating their collection, rather 



