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THE POPULAR SCIENCE MONTHLY. 



larging slightly toward the capitate end, which has also a slightly 

 indurated point. It is impossible to follow it with the unaided 

 eye, or in fact with an ordinary lens, even if the pistil be at once 

 plucked and dissected; but, by means of careful microscopical 

 sections, we may trace its course, as shown in Figs. 8 and 9. 



The larva hatches in about a week and will be found at a point 

 from eight to ten ovules above or below the external puncture, 

 according as the egg was thrust above or below it. It has no 

 pro-legs, but has well-developed thoracic legs. It matures with 

 the ripening of the seeds, which differs in time in the different 

 species of yucca, and also in the same species, but occupies on an 

 average about a month in the ordinary Yucca filamentosa. The 

 number of seeds destroyed is rarely more than a dozen and more 

 frequently less, and I have recorded the fact of having found as 



8. Transverse Section of Pistil, about middle, one day after oviposition, showing 

 (a, a) puncture of ovipositor, and (b, b) position of egg. 



many as twenty-one larvae in a single pod. Just about the time 

 the pods are hardening and ready to dehisce and the seeds have 

 already colored, the full-grown larva bores its way out of the pod 

 and makes its way to the ground. It remains as a larva within its 

 cocoon during the fall, winter, and spring months, and only trans- 

 forms to the chrysalis state a few days before the blooming of the 

 yuccas. The chrysalis (Fig. 4), as shown in the figure, is armed 

 with an acute spine on the head and with singular spatulate 



