l8o TRANS. ST. LOUIS ACAD. SCIENCE. 



gested by Dr. Engelmann {ante p. 29), that self-fertilization may 

 exceptionally take place. The first view may not appear very 

 plausible, but, to quote from the Report mentioned, "if both sexes 

 of the insect were, by some chance, introduced into a locality 

 where Yuccas of blooming age were growing, there is no reason 

 why they should not multiply ; and such chance introduction 

 is not impossible, since the larva not unfrequently remains in the 

 capsule after the seed is ripe, where it fastens a number of the 

 riddled seeds together into a sort of coeoon, which might easily 

 pass unnoticed in gathering seed ; and, if buried in the ground 

 with such seed, would in time give forth the moth." 



As bearing on the subject of the insect's range, we have proof 

 that it occurs on Long Island and around New York. Since writ- 

 ing my former paper I have examined the wild T. angustifolia 

 around Manhattan, Kansas, and always found traces of Pronuba; 

 but of seventy plants, including several species, examined in the 

 garden of Mr. Meade Woodson, of Kansas City — a gentleman who 

 is a great admirer of the genus — not one has yet produced seed. 

 Mr. Edgar Sanders, of Chicago, tells, me that plants of T. Jlac- 

 cida do not there produce seed. Mr. Henry Wheatland, of Sa- 

 lem, Massachusetts, says that T. Jilamentosa never produces seed 

 there ; "and I learn from Professor Gray that it is equally barren 

 at Cambridge. 



