74 TKOPICAL NATU:RE, AND OTHER ESSAYS. 



over with scales and spangles of metallic green, deepen- 

 ing occasionally into blue or golden or deep red spots. 

 Others again have spots and markings as of molten silver 

 or gold, while several have changeable hues, like shot- 

 silk or richly-coloured opal. The form of the wings, 

 again, often attracts attention. Tailed hind-wings 

 occur in almost all the families, but vary much in 

 character. In some the tails are broadly spoon-shaped, 

 in others long and pointed. Many have double or 

 triple tails, and some of the smaller species have them 

 immensely elongated and often elegantly curled. In 

 some groups the wings are long and narrow, in others 

 strongly falcate ; and though many fly with immense 

 rapidity, a large number flutter lazily along, as if they 

 had no enemies to fear and therefore no occasion to 

 hurry. 



The number of species of butterflies inhabiting any 

 one locality is very variable, and is, as a rule, far larger 

 in America than in the Eastern hemisphere ; but it 

 everywhere very much surpasses the numbers in the 

 temperate zone. A few months' assiduous collecting in 

 any of the Malay islands will produce from 150 to 250 

 species of butterflies, and thirty or forty species may be 

 obtained any fine day in good localities. In the 

 Amazon valley, however, much greater results may be 

 achieved. A good day's collecting will produce from 

 forty to seventy species, while in one year at Para about 

 600 species were obtained. More than 700 species of 

 butterflies actually inhabit the district immediately 

 around the city of Para, and this, as far as we yet 

 know, is the richest spot on the globe for diurnal 

 lepidoptera. At Ega, during four years' collecting ; 



