620 ON THE OVIPOSITION OF THE YUCCA MOTH. 
Analogy has proved an unreliable guide in this instance, as, 
indeed, it often does in natural science; while the curious Q 
Pronuba adds one more to the anomalies which belong to her. 
She does puncture the young fruit and convey her eggs into it 
from its side. 
The yucca flowers are fully opened and perfect during a single 
evening and night only, and it is during this, the first night of 
blooming, that eggs are consigned to the somewhat prismatic pis- 
til. The pollen grains are not so often expelled, to fall on the in- 
side of the flower, as I had been led to suppose ; but almost always 
remain in an entire lump on the contracted and curled anthers. 
The moth, consequently, has no difficulty in accumulating her little 
load of pollen, for a single anther furnishes nearly the requisite 
amount. 
Once equipped with this important commodity, she may be seen 
either crawling over or resting within the flower. From time to 
time she makes a sudden start, deftly runs around and among the 
stamens, and anon takes position with the body between and the 
legs straddling some two of them—her head turned toward the 
stigma. As the terminal halves of the stamens are always more 
or less recurved, she generally has to retreat between two of them 
until the tip of her abdomen can reach the pistil. As soon as a 
favorable point is reached — generally just below the middle—the 
lance-like sheath of the ovipositor, which consists of four converg- 
ing, corneous bristles, is thrust into the soft tissue, held there a few 
seconds while the egg is conducted to its destination, and then with- 
drawn by a series of up and down movements. So intent is she 
upon this work that after the ovipositor once penetrates the pistil 
the whole perigon may be detached, some of the encumbering 
petals and stamens removed, the insect brought within the focus 
of a good lens and all her movements observed to the greatest 
advantage, without disturbing her. In this way I have been able 
to watch the consignment of hundreds of eggs, and to admire the 
delicacy and elasticity of the ovipositor proper, which issues from 
the setaceous sheath in a silk-like thread, almost invisible to ome 
naked eye and as long as the terminal abdominal joint ; and which 
stretches and bends according as the body is raised’ or lowered. 
No sooner is the ovipositor withdrawn into the abdomen than 
the moth runs up to the top of the pistil, uncoils her rer 
cee thrusts them into the stigmatic — 
