Guests Welcome and Unwelcome 233 



yellow, and have no lines to show where the nectar is, 

 for these also would not be visible ; but they are often 

 so sweet as to be scented from afar. The large white 

 bindweed, though it opens by day, remains open at 

 night, when the moon shines, but not otherwise, to receive 

 the visits of moths. 



Wherever, in any part of the world, there is a dearth 

 of bright-coloured flowers, there, as a rule, there is a 

 scarcity of insects, and vice versa, for, where insects 

 are wanting, there the flowers fertilized by them cannot 

 of course flourish. 



The scarcity of both these is very conspicuous in the 

 Galapagos islands, situated on the equator, some 700 

 miles west of South America. In Juan Fernandez also, 

 which lies about 400 miles off Chili, ferns form the 

 larger part of the vegetation, as they do in most of 

 the South Sea islands. But there is no such total 

 absence of showy blossoms in Juan Fernandez as in the 

 Galapagos. One shrub which flourishes there bears 

 snowy blossoms, like those of the magnolia ; another, 

 also plentiful, has dark blue flowers ; and besides 

 these, there are large patches of a white, lily-like bulb, 

 and there are two conspicuous yellow flowers as well. 



Yet Juan Fernandez is poor in insects. It has but 

 one butterfly, and that is rare; there are only four 

 species of moths, and no bees at all, but some which 

 are very minute and of no more use to large blossoms 

 than the flies, of which there are twenty species. 



But the poverty of the insect-life is made up for by 

 the presence of humming-birds, which are so abundant 

 that there are one or two in every shrub ; and these 

 when killed are usually found with the front of their 

 heads covered with pollen. 



