110 



flower remains open for a single day, on the second day the 

 ends of the six stamens begin to close up and the flower has 

 the shape of a balloon with six small openings. At twilight 

 and during the night, there is flying about the flowers of the 

 yucca a yellowish white moth with a metallic luster, the 

 Pronuha yuccasella. The flrst joint of the maxillae is extraor- 

 dinarily lengthened, and on the inner side it is provided with 

 stift bristles. It can be rolled up as a proboscis. This struc- 

 ture is for the purpose of collecting, rolling up and holding 



FIG. 48. 

 Fig, 48. Moth with a ball of pollen. (After Riley). 



the pollen. The females of the moth enter the open flower 

 and obtain the pollen, not however to eal, but to carry 

 it to another flower. In a short time the moth has col- 



