-^33- 



' Mr. HULSTS OBSERVATIONS ON PRONUBA 

 YUCCASELLA. 



By Prok. C. V. Rii.EY. 



On page 184, current volume of "Entomoi.ogica Amkricana", Mr. 

 < leo. D. Hulst is reported as making the following statements in refer- 

 c-nce to Pronuba yuccasella, and I assume correctly since, being one of 

 tiie editors, he has opportunity to read and probablv write his owa state- 

 ments: 



"Prof. Riley, after many and extended observations, gave the his- 

 liiry of the fertilization of this plant, concluding that the moth is a neces- 

 >-ity to the continuation of the plant, that fertilization was effected by ii 

 alone and that every developed sped vessel bore evidence of the work of 

 the Moth by the presence of the larvae within the capsule." 



He then refers to the method of oviposition and pollination l)y tlii> 

 moth as de.scribed by me, and states that his observatiojis have not 

 lirought him to the same conclusion arrived at by me. He further states 

 his belief that there must be very extensive fertilization of this plant b\ 

 honey bees, because he found these '"plentiful about the flowers"; that 

 die majority of the seed capsules examined by him showed no indication 

 <if larvae of any sort; and finally refers to the fact that Yucca is sometimf"- 

 fertile in foreign countries. 



There much error and uinvarranled conclusion in the two short 

 paragraphs in which the above information is vouchsafed. 



For over 16 years now I have very carefully studied the habits «.>f 

 Pronuba in connection with Yucca, not in one localitv alone but in 

 nearly every State east of the Rocky Mountains where that genus occur.v 

 either indigenously or by introduction. ' I have also had occasion io 

 study it in many places in Europe in which it is cultivated, and the re- 

 >ults have been published in several papers. 



In reference to honey bees frequenting Yuccas it is rather strangf 

 that Mr. Hulst's experience differs .so from mine: for, so far as my ex- 

 perience goe.s, neither honey bee nor any other honey-loving Hvmenoj*- 

 lera frequent the Yucca flowers and this is what we should expect from 

 the very nature of these flowers They 'iire half clo.sed during the da> 

 and do n(,)t open until toward evening whert bee's are hiveward bound: 

 the anthefs do not open till then and the pollen is glutinous,adheringin 

 lumps, either on the curled anthers or to the inside of the perianth. li 

 would not adhere to hirsute Hymenoptera, and in point of fact the.se aro 

 not found in the flowers. I have given a list of the insects most freqi»"ni- 



