200 OUR INSECT FRIENDS AND FOES 



in the flowers, and in doing so become loaded 

 with the pollen from the flower upon which they 

 have rested ; in subsequently visiting other 

 flowers, they dust the stigmas with the pollen 

 from the flower which they had previously 

 visited. At first one would be inclined to suppose 

 that the depositing of eggs in the flowers, the 

 subsequent emergence of the larvae, and their 

 feeding upon the ovules within the shelter of the 

 ovary, would be anything but advantageous 

 to these flowers. This, however, is not the 

 case, for owing to the large number of ovules 

 which the flower produces, they are rarely all 

 devoured, and even should this occur in one 

 seed-capsule, there are always other capsules 

 on the same plant uninjured, and capable of 

 producing a sufficiency of seed. 



That charming writer and eminent authority 

 on the reciprocal relations existing between 

 plants and insects, Anton Kerner von Marilaun, 

 gives the following intensely interesting account 

 of the relations existing between the flowers of 

 the Yucca and a small moth, and between the 

 Fig and a minute Hymenopterous insect : " The 

 life-history of one of the moths living on 

 the capsule-bearing species of the genus Yucca, 

 and named Pronuba yuccasella, has been made 

 out, and affords one of the most wonderful 

 examples of the dispersal of pollen by means 

 of egg-laying insects. The flowers in all species 

 of Yucca are arranged in large panicles, and 

 each is bell-shaped and suspended at the end 

 of a smooth, green stalk. The perianth-leaves, 

 six in number, are yellowish-white, and are 



