184 MYSTERIES OF THE FLOWERS 



in the capsule just suited to their taste, till they 

 grow large enough and strong enough to go forth 

 and burrow into the ground. 



It is, then, to make a home and provide food for 

 her babies that the moth fertilises the Yucca. Where 

 there is no Yucca Moth there are no Yucca seeds 

 formed. In Mexico and other regions where the 

 Yucca is indigenous, the Pronuba Yuccasella also is 

 found. In our northern region, till recently, there 

 were no moths and consequently no seeds were set. 

 I read in Mr. Gibson's "Notes" of twenty years ago 

 that the Pronuba had not yet arrived in Washing- 

 ton, Connecticut, and Yucca plants then bore no 

 seeds. But since then the moth has evidently come 

 hither, for in 1913 I found a Yucca plant near my 

 home bearing many seed-capsules, and to test 

 their fertility I planted a handful of their seeds 

 and thus have reared a sturdy little colony of 

 Yucca plants, the first of their kind here grown 

 from seed. 



The interdependence of flower and moth, this 

 altruism more than human, so exceptional, suggests 

 a path of investigation well worth following. The 

 relations of all insects to all plants have not yet 

 been investigated. We have been fortunate enough 

 to learn of a pair which depends for life, each upon 

 the other. There may be, and probably are, other 



