Eastern PieridcB. 



303 



tlie earth, but never extend far northward of the tropics. Col'uts 

 and Anlliocharis on the other hand are Arctic and Alpine, oc- 

 curring in both continents and in both hemispheres, but rarely 

 extending into tropical lowlands. In most of these widely dis- 

 tributed genera the species also have a wide range, and some 

 specific forms of Callidnjas, Tachyris and Terias are almost 

 identically reproduced in the eastern and western tropics. Most 

 of these are insects which roam about cultivated grounds and 

 river banks, and collect in swarms on wet and muddy shores ; while 

 the more restricted species and genera, such as Euterpe, Leptalis, 

 Leucophasia, Elod'ina, Thyca and Eron'ia, are inhabitants of woods 

 and forests, and become quickly exterminated by the advance of 

 cultivation. 



The following table exhibits the distribution of the genera of 

 Picrldce throughout the six zoological divisions of the earth, with 

 the number of species of each described up to this time. 



Y 2 



