70 Riley Presidential Address. 



some plant or other near by. They are generally seen in double column, 

 one column ascending the plant and cutting off the leaves, and the other 

 returning loaded to the nest. Great intelligence is shown by this ant in its 

 foraging expeditions. The cut leaves, either whole or in circular pieces, are 

 usually thrown on the ground by those who ascend the tree, while others 

 below receive and bear the fodder home. Each piece of leaf is grasped 

 by the jaws, and, with a quick motion of the head, thrown back over the 

 head and thorax in such manner that it lodges edgewise in a deep fur 

 row and between two spines which characterize the head, so as to cover 

 the insect more or less and offer little or 110 obstacle to its progress. 

 Very long underground tunnels are sometimes excavated from the main 

 formicary to some shrub or tree so as to facilitate access thereto. The 

 stories told by southern planters of the ravages of this insect seem almost 

 incredible, but I have myself witnessed the utter denudation of a large tree 

 in a single night, in which case all the forces of the formicary seemed to 

 be concentrated on a single object. 



Atia tardigmda is found east of the Mississippi River, occurring through 

 out the gulf States from Florida to Texas. In Florida what is evidently 

 this species builds rather large cells from two to four inches in diameter in 

 fine white sand, the walls very firm and smooth. In some instances the 

 walls are said to be lined with a kind of curtain composed of particles of 

 different colored sands brought up from a lower stratum and interwoven 

 with fine white threads, by which is doubtless meant shreds of the refuse 

 vegetation collected a kind of spongy mass, manufactured from the vege 

 tation and somewhat resembling the comb made by certain bees. This 

 spongy mass contains small irregular pockets, apparently designed for the 

 reception of the young, and in this we have the nearest tendency in ants to 

 the building of cells which is so common in some of the other social Hymen- 

 optera. This species prefers the fine needle-like leaves of tender pine seed 

 lings, and a row, marching in single file, each carrying a piece of one of 

 these needles, suggests a file of soldiers armed with rifies. 



Atta mexicana Sin. abounds in the temperate regions of Mexico, its formi 

 caries being twenty or more feet in diameter, and a funnel is said to extend 

 through its center to facilitate drainage, which would seem to be necessary 

 in a country subject to very heavy rains. The damage done by this species, 

 especially to coffee plantations, is said to be very great. 



Atta ccpkalotes L. is dreaded in .Brazil because of its destructiveness to 

 vegetation and of its tendency to enter houses and carry off the mandioca 

 rneal. Its formicaries often reach a diameter of more than 100 feet. 



NKST-BUILUING ANTS. Though we have in the United States no species 

 which constructs nests similar to those of wasps, yet such are known to 

 occur in other parts of the w r prld, especially in tropical and sub-tropical 

 countries. The genera Polyrhacis, Doliehoderus and Oernastogaster imitate 

 wasps in the construction of their nests. 



Some of the Brazilian species of Cremastogaster construct more or less 

 globular, black nests, about the size of a human head, fastened between the 

 branches of trees, large numbers of which may often be noticed among the 

 mangrove bushes bordering the shores of the ocean, and frequently so low 

 down as to be but a few inches above high tide. Similar nests are common 

 in the West Indies, and look very much like young nests of Eutermes. 



The nest of Cremastogaster arboreus Sm., found at Port Natal, Africa, is 

 very large, measuring about fifteen inches in length, by nine inches in 

 diameter. It is always built around a branch, resembles in texture and ap 

 pearance the nest of our common paper wasp, Vespa macnlata, and contains 

 thousands of the insects. (See Smith, Cat., Hym. Ins. Brit. Mus. Pt. VI. 

 pi. XIV. 



We see the beginnings of the nest- building habit in some of our North 

 American species, especially in Cremastogaster lineolata Say, which builds 

 coverings over colonies of Aphides, the coverings composed of minute par 

 ticles of vegetable and earthy matter firmly glued together ; or else makes 



