ANTS. 81 



harmless, others exceedingly destructive. The number 

 of different kinds is very great. In India and the 

 Malay Archipelago nearly 500 different species have been 

 found, and other tropical countries are no doubt equally 

 rich. I will first give some account of the various 

 species observed in the Malay Islands, and afterwards 

 describe some of the more interesting South American 

 groups, which have been so carefully observed by Mr. 

 Bates on the Amazon and by Mr. Belt in Nicaragua. 



Among the very commonest ants in all parts of the 

 world are the species of the family Formicidse, which do 

 not sting, and are most of them quite harmless. Some 

 make delicate papery nests, others live under stones or 

 among grass. Several of them accompany Aphides to 

 feed upon the sweet secretions from their bodies. They 

 vary in size from the large Formica gigas, more than an 

 inch long, to minute species so small as to be hardly 

 visible. Those of the genus Polyrachis, which are 

 plentiful in all Eastern forests, are remarkable for the 

 extraordinary hooks and spines with which their bodies 

 are armed, and they are also in many cases beautifully 

 sculptured or furrowed. They are not numerous indi- 

 vidually, and are almost all arboreal, crawling about 

 bark and foliage. One species has processes on its 

 back just like fish-hooks, others are armed with long, 

 straight spines. They generally form papery nests on 

 leaves, and when disturbed they rush out and strike 

 their bodies against the nest so as to produce a loud 

 rattling noise ; but the nest of every species differs from 

 those of all others either in size, shape, or position. As 

 they all live in rather small communities in exposed 

 situations, are not very active, and are rather large and 



G 



