24 Riley — Presidential Address. 



tropical countries. Some two hundred species have already been 

 described from North America, many of which are nearly related 

 to or even identical with those of Europe; while some are cosmo- 

 politan, having been distributed by the agency of man over almost 

 every part of the world. One of the best known of these cosmo- 

 politan forms is the the little Red Ant, 7l/f>/K>/»or/(i(j» p/;/(mo/H's 

 Linn., a grievous household pest. Under the tribal term Ileter- 

 o(/ijii(( Latreille, the ants are divided by the later systematists 

 into four families (by some considered sub-families), namely, the 

 Fornncida', the Pouerida^ the Dorilida^ and the Myrmicid^e. The 

 lirst family, Formicida;, comprises all those species which are des- 

 titute of a sting, ex';ept in the genus CEcophylla, and are further 

 characterized by having but one node or scale connecting the ab- 

 domen with the thorax, and by the habit in the larva of construct- 

 ing for pupation, a dense, smooth, ovoid, silken cocoon. The re- 

 maining families are possessed of a sting, the Ponerida? agreeing 

 with the Formicida^ in the cocoon-forming habit of the larva and 

 in having but a single node or scale connecting the thorax and ab- 

 domen, l)uc having an additional, more or less pronounced con- 

 striction between the first and second abdominal joints. The 

 Dorilida^ are somewhat aberrant, the female and worker, so far 

 as known, being blind, and nothing being yet known of their 

 larva3. In the last family, the Myrmicida?, there are two well- 

 developed, freely mobile nodes between the abdomen and the 

 thorax, and the larva; are unprotected by any cocoon during 

 pu])ation. The most interesting and destructive species occur 

 in this family. 



Let us glance brielly at some of the species, more according to 

 habit, however, than this classification, and preferably our North 

 American species. L'hus they may be considered as Carpenter, 

 Mound-building, Harvesting, Honey, Leaf-cutting, Nest- building 

 and Driving or Foraging ants. (Note 5.) 



Ant Economy and Habits. 



AisTT Wars. — Very many most interesting accounts of the intel- 

 ligence and battles, and of the curious persistency of ants, espec- 

 ially of the foraging species, are recorded by travellers in tropical 

 countries, and particularly by the late Henry Walter Bates in 

 his " Naturalist on the Eiver Amazons ". It is a well established 

 fact that ants, like human beings, do at times declare war against 



