On Pronuha Yuccasella. 147 



those of kindred species calls for a like explanation. What explana- 

 tion can be offered? Does it aid in the fertilization of the flowers? Mr. 

 Riley has hitherto claimed for P. yuccasella alone, the office of marri- 

 age priest to the yuccas.. Does the larva feed in any way upon the 

 plant? With all Mr. Rile3-'s diligent observations upon yucca-feeding 

 insects, he has failed to discover this larva, notwithstanding the abund- 

 ance of the imago. Does the imago feed in the flowers? There is no 

 evidence conducing to establish the fact. In no instance was it ob- 

 served feeding, but always quietly reposing, like P. yuccasella, in the 

 same position with it, and in company with it within the perianth. Was 

 it there for protection? And does it again return to the wooded region 

 where nobody ever saw it, to oviposit, where its invisible larvse feed on 

 invisible leaves, construct invisible webs, and in time produce moths 

 which are never seen except in the flowers of the 3'ucca, miles away? 



But Mr. Rilej^ has foreseen the difficult}-; he has foreseen the neces- 

 sity of accounting for the presence of the Hyponomeata in yucca 

 flowers, with P. yuccasella, and under all the circumstances above de- 

 tailed. His explanation is that " white moths are naturally attracted 

 to white flowers, and it is rash to assume, without careful examination, 

 that all white moths found in j-ucca flowers are Pronuha^ I have made 

 no such assumption in so many words. If I have made any assumption, 

 it extends no further than these particular moths. But, in point of 

 fact, no white moths, other than these (including the true Pronuba) 

 ever have been found there; that is a fact, not an assumption. "White 

 moths are naturally attracted," etc., no doubt, if they are attracted at 

 all. "Naturall}-" explains this phenomenon in the same wa}' that the 

 word " gravitation" explains why a stone falls. It is a word to cover 

 our ignorance of a vera causa, and to my mind, the sentence just quoted 

 from 3Ir. Rile}^ reads much more like a deduction from some theory of 

 •'protective resemblance," or mimicry, than like an induction from 

 observed facts; and whatever may be true of other moths, I assert, 

 without hesitation, as to the Tineina, that white moths are not natur- 

 all}' attracted to white flowers; exactly the reverse is the case. It is 

 a most extraordinary circumstance to find a lohite moth of this family 

 in a v^hite flower, or on a flower of any kind. If Mr. Riley is right 

 in referring these specimens to Hyponomeuta, it is the first recorded 

 instance in which a Hyponomeuta has ever been found in a flower, 

 white or colored. Na}^, further, excepting these Colorado species, 

 and the European Anesychia decemg^ittella (to which I shall 

 refer again further on), two, or at most three, species, no white 

 moth of the family Tineina has ever been recorded as being found 

 on or in a white flower. If a single such instance occurs, I have 

 not been able to find a reference to it. But, again, Blastobasis gigan- 



