18 NATURAL ENEMIES. 



operation of which a numerical balance of life or 

 of living beings is maintained in nice equili- 

 brium and the vast number of insectivorous 

 birds, amongst which the Trochilidae are not the 

 least active, proves that, in the economy of 

 nature, an incessant warfare against the insect 

 world is essential. We may not, perhaps, at 

 first perceive the necessity of this ; but a little 

 reflection will convince us of it ; and accordingly 

 we find that where insect life teems in profusion, 

 there will the insect-destroyers abound in due 

 proportion. Such is the polity of nature. 



All living things have their destroyers even 

 the parasitic worm has its parasites - and no 

 doubt the Humming-birds have in their turn 

 their enemies, though perhaps to a far less ex- 

 tent, than have granivorous or graminivous 

 races (we may apply the observation generally 

 to quadrupeds as well as birds), whose ravages 

 unchecked would unclothe the fields and over- 

 throw the forests. But whatever natural ene- 

 mies the Humming-bird may have, Madame 

 Merian's great spider is not one, although Les- 

 son gives his authority for the fact. 



It is somewhat interesting to trace the origin 

 of the belief so recently entertained relative to 

 the bird-catching spiders, a belief not altogether 

 abandoned, inasmuch as credulity is congenial 

 to common minds. Oviedo, in 1547, and Pere 

 Labat in his account of " Les Isles de Bermu- 

 dez" (1640), describe spiders which make webs 



