128 THE CANADIAN ENTOMOLOGIST. 



been traced to organic germs — in few words, a first-class scientific student, 

 who, after careful investigation of the fungus-killed insects brought to him 

 by the " practical " entomologists, shall inform the latter of the nature 

 of the fungi, whether they are transmutable or fixed in structure,* how 

 they can most advantageously be cultivated, and in what vehicle they can 

 best be distributed when needed. 



Is there any resemblance between these two pictures ? 



A MYSTERY IN REFERENCE TO PRONUBA YUCCASELLA. 



BY DR. H. A. HAGEN, CAMBRIDGE, MASS. 



June 6, 1880. 



Last summer Dr. Geo. Engelmann saw some parts of the biological 

 collection here, and was so kind to promise me his help to obtain some 

 species, which I was very eager to possess, viz., Promiba yuccasella in its 

 different stages, and Phylloxera. By his request, I received through the 

 kindness of Mr. Thos. Meehan, in September, two bundles of the stems of 

 Yucca filamentosa and angustifolia. The latter species, after a careful 

 examination of every stick, was found to be entirely free of insects or 

 larvae ; but the former contained many numerous small green larvae in 

 silky cocoons (and no other kind of larva), placed through the whole 

 length of the stem and in every direction. I compared the larva with 

 Mr. Riley's figure and description of Pr. yuccasella, and as both disagreed 

 — the larva having no legs at all — I believed it to be a new Rhynchophorous 

 larva at least unknown to me, and wrote accordingly to Mr. Thos. Meehan. 

 Having placed some larvae in alcohol, I postponed further investigation 

 until they would be more advanced ; but they lived through the whole 

 winter, and did not increase in a marked manner. 



How was I surprised when, in May, I found in the jar where I kept 

 the stems two moths of Pronuba yuccasella ! I believed at first that I had 

 overlooked their larvae, and that, after Mr. Riley's description, they had 



* As this is a subject of which little is known, it offers a most promising field for 

 squabbling, and in fact is being already cultivated for that purpose, with prospects of an 

 abundant crop of prematurely expressed opinions. 



