PLANTS THAT ENTERTAIN 153 
with great care. In and out among the flower she 
crawls and flits, scraping a bit of pollen from this 
anther and a bit from that. Finally, when enough 
pollen has been gathered to form a ball twice the size 
of her head, she carries it to another flower. In the 
pistil of the new flower she darts her ovipositor, 
making a tiny nest in the soft tissue, where she 
imbeds her first egg. Her next move is to mount 
to the top of the style and place the ball of pollen 
on the stigma, forcing it down into the tube, that 
it may serve as a cover and protector for her egg. 
Incidentally, both egg and pollen reach the ovary 
of the flower, thus fertilising it. Sometimes the 
moth deposits more than one egg in a pistil, but 
each egg is placed in a different part, and a fresh 
act of pollination follows; as if she were making 
payment in advance for the care which the yucca 
is to give to each of her babies. 
This is a case of exchange—one of the multitude 
of instances that are found occurring between mem- 
bers of the plant and the insect kingdoms. ‘The 
yucca nourishes and cares for the family that it 
entertains: the moth fertilises its generous hostess. 
When the moth’s egg finally hatches, the larva 
finds itself in a very “garden of paradise.” Here 
it feasts on the delicate tissue of the plant until the 
plant’s own seeds are ripe, when the larva bores 
