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THE POPULAR SCIENCE MONTHLY. 



abdomen pressed down between them. From the tip of the abdomen 

 the long, sharp-edged ovipositor, an organ of wonderful delicacy 

 and most remarkable structure, is thrust into the tissue of the 

 pistil, and the eggs are deposited among the ovules. This act 

 may occur several times on the same pistil. Then, still more re- 

 markable, the moth deliberately runs to the apex of the pistil and 

 with tongue and palpi crams a portion of the collected pollen 

 mass into the stigmatic tube, thereby fertilizing the flower. The 

 tongue is worked up and down for some time in the tube like a 

 piston rod, with evident intentness on the part of the moth. This 



Fig. 11. — Pronuba 

 yuccasella. 



Fig. 12. — Fkuit of Yucca glokiosa. 



series of operations, always in the same order, may be repeated 

 again and again till late into the evening. The moth chooses only 

 the freshly opened flowers and those that have not been punctured 

 by another moth coming before. Only the flowers thus fertilized 

 can ever by any possibility produce fruit; and thus the yucca 

 fruit, as seen in Fig. 12, always bears several constrictions 

 where the scar was made by the puncture of the moth's oviposi- 

 tor. Inside the fruit the moth-larva develops with the seeds, de- 

 vouring sometimes a dozen of them ; and when the pod ripens 

 the larva eats its way out, and, in the night-time, drops to the 

 ground by a silken thread, burrows into the soil, and the^e wraps 

 itself in a strong cocoon. Sometimes the moth does not issue 



