POLLINATION OF YUCCA AND FICUS 



103 



of Yucca in question, while in the absence of the appropriate moth not a single seed 

 would be set. 



A relation between flowers and insects as remarkable as that presented by Yucca 

 and its moth, obtains between the figs (Ficus Carica and others), and certain small 



Fig. 17. Transjer of pollen by egg-laying insects, (i) A branch of the inflorescence of Yucca 

 Whipple! ; the flower in the middle is open, the one below it, which was open the previous day, is already 

 closed, the other flowers are still in the condition of buds. (2) A single flower of the same plant visited 

 by the moth Pronuba Yuccasella ; the three anterior petals removed. (3) Stigma of Yucca Whipplei. 

 (4) Pronuba Yuccasella flying to Yucca Whipplei in the moonlight. (5) Head of the insect, with its 

 proboscis-like maxillary palps, holding fast a ball of pollen. (6) Branch of Ficus pumila with urn- 

 shaped inflorescence divided longitudinally. (7) A single female flower from the base of this urn. 

 (8), (9) Stamens from the upper part of the same. (10) Urn of Ficus Carica filled with galls produced by 

 Blastophaga, and divided longitudinally ; near the mouth of the urn is a fig-wasp (Blastophaga grossorum), 

 which has escaped from one of the galls. (11) Urn-shaped inflorescence of Ficus Carica filled with female 

 flowers, and divided longitudinally ; at the mouth of the urn are two fig-wasps, one of which has already crept 

 into the interior, while the other is in the act of doing so. (12) Male flower. (13) Long-styled female flower 

 of Ficus Carica. (14) Gall produced by a short-styled gall-flower. (15) Blastophaga grossorum escaping 

 from a gall. (16) A Blastophaga that has escaped. (17) The same enlarged. Nos. i, 2, 4, 6, 10, xi, 16, 

 natural size ; No. 3, X2; No. 5, X20; Nos. 7, 8, g, 12,13, ^5: Nos. 14, 15, 17, x8. (After Kerner.) 



