152 THE HUMAN SIDE OF PLANTS 
break their petals when a bee or a butterfly alights 
upon them. This lack of hospitality is accorded 
by the hemlock stork’s-bill. 
Perhaps of all plant-hostesses the yucca stands 
first. The yucca is not unselfish in her elegant 
manner of entertaining; neither is she unwise. She 
is well repaid for all her trouble in entertaining her 
guests—she has but one kind, the yucca-moth. 
The yucca and her guest are inseparable: where 
one is found, there also is the other. Examine 
the yucca blossom and you will always find in it 
the delicate, fairy-like guest, draped in her 
strangely beautiful white costume. If it is day- 
time, the guest will be resting with folded wings, 
waiting for the busy night hours; for then she has 
work to perform. 
The male yucca-moths are seen more often than 
the females. They flit from flower to flower in the 
evening, gathering pollen and looking after out- 
side affairs in general, while their mates are busily 
engaged in the flowers. The female moth has no 
time for visiting among her neighbours, for she 
mustconstantly attend to her household duties. She 
must prove a satisfactory guest, reciprocating the 
generosity of the plant, which produces food for her 
offspring. This the moth does by gathering to- 
gether large balls of pollen, packing and rolling it 
