RILEY — GENUS PRONUBA ; FERTILIZATION OF YUCCA. 63 



our Pronuba's history, as here given, can be positively substan- 

 tiated, let me hope that the next blooming-season of our Yuccas 

 will find other eyes than my own watching her ways and methods. 



We have in this little moth a remarkable adaptation of means 

 to an end. There is between it and its food-plant a mutual inter- 

 dependence which at once excites our wonder, and is fraught with 

 interesting suggestions to those who are in the habit of reasoning 

 from eftect to cause. Whether we believe, as I certainly do, that 

 this perfect adaptation and adjustment have been brought "febout 

 by slow degrees through the long course of ages, or whether we 

 believe that they always were so from the beginning, they are 

 equallv suggestive of that same law and harmony so manifest 

 throughout the realm of Nature. 



The peculiar structure of the flower which prevents self-fertili- 

 zation, though on a superficial view it strikes one as a disadvan- 

 tage, is in reality a great benefit ; while the maxillar}' tentacle 

 of the female moth is very plainly an advantage to her species in 

 the " struggle for life" ; and it is quite easy to conceive, on Dar- 

 winian grounds, how both these characters may gradually have 

 been produced in the course of time from archetypal forms which 

 possessed neither. These peculiarities are, moreover, mutually 

 and reciprocally beneficial, so that the plant and the animal are 

 each influenced and modified by the other, and the same laws 

 which produced the beneficial specialization of parts would main- 

 tain them by the elimination of all forms tending to depart from 

 them. 



It may be that the glutinous nature of the pollen renders con- 

 sectaneous its accumulation by the spinous maxillary tentacles of 

 the female moth ; and that, when she is sipping nectar, the vigor- 

 ous working of head and body from side to side is simply an eflbrt 

 to get rid of an incumbrance. It may be that all her actions are 

 the result merely of " blind instinct," by which term proud man 

 has been wont to designate the doings of inferior animals ; but for 

 my part I have not been able to watch her operations without feel- 

 ing that there is in all of them as much of purpose as there is in 

 those of the female Pelopceus, who so assiduously collects, para- 

 lyzes, and stores away in her mud-dabs, the spiders which are to 

 nourish her young ; or in the many other curious provisions w^hich 

 insects make for their progeny, which, in the majorit}' of instances, 

 they are destined never to behold. Nor can I see any good reason 



