THE YUCCA MOTH AND YUCCA POLLINATION. 175 



large load of pollen for the purpose of pollination. Another or- 

 gan which is characteristic is the ovipositor (Fig. 4, b, d), which 

 is delicate and ex- , . 



tensile, being a com- 

 bination of lance 

 and saw, and admi- 

 rably adapted for 

 cleaving through 

 the young fruit and 

 then running the 

 long 

 filiform, into 

 the ovarian cavity. 

 Though all the 



egg, which is 

 and 



Fig. 4. Genital Characters of Pronuba yuccasella : a, tip 

 of <j> abdomen rendered somewhat transparent; b, basal 

 joint of ovipositor ; c, its sculpture ; d, terminal joint of 

 same ; e, tip still more enlarged ; f, genitalia $ from side ; 

 <7, genitalia $ from above ; h, undeveloped egg from ovary 

 enlarged. 



acts of the female 

 are nocturnal, it is 

 not at all difficult 

 to follow them with 

 a la,ntern, for, albeit 

 ordinarily shy, she may be closely approached when she is about 

 to oviposit. Her activity begins soon after dark, but consists at 

 first in assiduously collecting a load of pollen. She may be seen 

 running up to the top of one of the stamens, and bending her head 

 down over the anther, stretching the maxillary tentacles, so won- 

 derfully modified for the purpose, to their fullest extent, the tongue 

 uncoiled and reaching to the opposite side of the stamen (Fig. 6). 

 In this manner she is able to obtain a firm hold of the same 

 while the head is kept close to the anthers and moved peculiarly 

 back and forth, something as in the motion of 

 the head of a caterpillar when feeding. The 

 maxillary palpi are Used in this act very much 

 as the ordinary mandibles are used in other in- 

 sects, removing or scraping the pollen from the 

 anthers toward the tentacles. After thus gath- 

 ering the pollen, she raises her head and com- 

 mences to shape it into a little mass or pellet by 

 using her front legs very much as a cat does 

 when cleansing her mouth, sometimes using only 

 one leg, at another time both, smoothing and 

 pressing the gathered pollen, the tentacles mean- 

 while stretching and curving. After collecting 

 all the pollen from one anther, she proceeds to another and re- 

 peats the operation, then to a third and fourth, after which, with 

 her relatively large load often thrice as large as the head held 

 firmly against the neck and front trochanters, she usually runs 

 about or flies to another plant : for I have often noticed that ovi- 



Fig. 5. Pronuba yuc- 

 casella : I, male ; 

 77i, female chrysalis 

 hair-line showing 

 natural size. 



