68 Riley — Presidential Address. 



nearly to the apex of tlie sclerite as in the case of the fertile female in Apis. 

 In Bombus the structure is almost identically the same as m Melipona. 



Note 5. — Ant Economy. 



Considering the large number of species of ants, a book would be re- 

 quired to treat of them in detail, and volumes iuive been written. In 

 this note I shall only treat of a few of the better known, to sup|ilement the 

 mere summary iu the body of the address The most interesting of our 

 North .American species which I have had an ojiportunity of studying are 

 the mound-building species of the East, the leaf-cutting species of Florida 

 and Texas, and the honey ants of Colorado. With the aid of Mr. Th. 

 Pergande, who has been assitluous in his studies of the family, and is per- 

 haps om" best-informed myrmecologist, I have brouglit together a number 

 of notes on the habits of our North American species of Carpenter Ants 

 and others; but they are excluded as the least important' in connection 

 with the text, and with a view of duly limiting the pages. 



MouNiJiu iLiuNG Ants. — In this category may be classed by far the 

 larger number of our better-known ants. The term is, however, jjarticularly 

 applicable to the species of the genus Formica. These ants are very much 

 more active and industrious and typical of the family, than are the carpen- 

 ter ants. Our own species inhabit, by i)reference, pine woods. They are 

 pugnacious and valiant, and whenever their mound is disturbed, however 

 slightly, will speedily cover the whole surface iu one surging mass, spread- 

 ing over the mound and attacking in their fury any living creatm^e within 

 reach. They are in fact so tierce and fearless that even man tloes 

 well to avoid their mounds ; for the bite is quite severe, and Avhen multi- 

 plied indelinitely is unbearable. 



The Fallow ant {Formica exsecioide.t Forel), one of om' best kno\ni species 

 and a close ally of F. exsectn of Europe, builds large mounds of earth, more 

 or less mixed with other materials, esjieciaJly small sticks and dried leaves 

 of pine. These will measure all the way from two to eight feet in diameter 

 at the base, and may be from one to three feet high. Tliey are more or less 

 regular and conical, full of galleries, with larger or smaller chambers which 

 communicate with a general system of subterranean cells or cavities, which 

 are used as store-rooms, nurseries for the young, parlors for the queens, and 

 other purposes. The purpose of the superstructure in most mound-build- 

 ing ants a]>pears to i;)e for aei'ation, for the more rapid development 

 of the larva', and, apparantly, to facilitate social intercouse between the 

 individuals when not engaged in actual work. Excejit for the extrane- 

 ous matter- which gives it lirmness, all the material of the mound is brought 

 up from beneath the surface, and the inhabitants are incessantly at work, 

 night and day, in constructing, alteruig and re]iairing. Very large 

 colonies are often connected by secondary hills. I once had a good oppor- 

 tunity of studying these mounds around Itliaca, N. Y., and Dr. H. C. IMc- 

 Cook has published a most interesting and detailed account of his observa- 

 tions upon this ant in the Trans. American Entomological ."^ot'iety for 1877, 

 Vol. VI, page 253, and also in Tlie Amencan Natvrnlist for July, 1878, Vol. 

 XII, pp. 431-445. It is i)articularly common in the Alleganies. There are 

 three forms of workers, viz, mnjor, minor and dwarf. His interesting ob- 

 servations will well reiiay reading. 



It is in these mound-building ants that we find the true economy of the 

 division of labor. While large numbers are ceaselessly building and min- 

 ing, so as to keep the formicary iu good condition, repairing or increasing 

 its size, so as to accommodate the growing numbeis, others are busily engagetl 

 in scorning the surrounding country for food, both for themselves, for the 

 multitude of those who staj^ at home, and for the young. In these exjiedi- 

 tions they never hesitate to attack any other insect that may be in their 

 way, no matter how much larger than themselves, and what they lack in 

 power individually they make up in numbers. Still others again are run- 



