FURTHER STUDIES OF YUCCAS. 213 



positing. While in this attitude they are very observant, 

 and the approach of one's face, even at a distance, causes 

 them to retire further down the pistil. When so disturbed 

 they are also very apt to drop suddenly from the flower and 

 take wing, seeking a new retreat. 



I have not seen the collection of pollen by the typical 

 form of this moth, but, from the way in which the load is 

 carried, there is no doubt that it is accumulated in the 

 manner presently to be described for the pollinator of what 

 I take to be the Yucca graminifolia of Wood, and I see 

 no reason to doubt that it frequently takes place in the 

 bright daylight, as both opposition and pollination do. 

 Either of the latter operations may be witnessed at any 

 time during the day, if the flowers are not approached 

 too suddenly. 



When the moth is about to deposit an egg, she usually 

 moves about in the lower part of the flower much as the 

 other species do, commonly dragging the tip of the ovi- 

 positor along the parts she walks on as if wiping off 

 extruded secretion, but also seemingly using it as a tactile 

 organ while she assumes the position best suited to ovi- 

 position, which is nearly the same as that taken while at 

 rest. Standing on the side of the pistil, she then bends the 

 abdomen sharply forward so as to bring the ovipositor 

 to about the middle of the ovary, which she pierces at 

 the thinnest part, namely, about 1 mm. from the septal 

 groove. As a general thing not more than six eggs are 

 laid in a given pistil, — one on either side of each septum, — 

 and frequently the number is smaller than this, so that 

 even if they all hatch, which is not likely to be the case, 

 there is rarely more than one larva to each tier of seeds, 

 and consequently a fair percentage of the seeds are allowed 

 to come to maturity. In the very succulent white ovary 

 the puncture made in laying an egg is usually seen easily 

 immediately after the ovipositor is withdrawn, and a rather 

 large drop of clear sap not infrequently exudes from it 

 within a short time. 



