72 Bulletin American Museum of Natural History. [Vol. XXII, 



Atlantic seaboard, as for example in the Ramapo Mountains, on Staten 

 Island, in the Litchfield Hills of Connecticut, and in the pine and beech 

 woods near Woods Holl, Massachusetts, are dome-shaped and do not 

 taper to a blunt point above like those figured by McCook. They are 

 often very low, rarely attaining a height of a foot or i8 inches, and are 

 usually surrounded by a broad circle of grass at the base, which may 

 be 3 or 4 feet in diameter. (Pis. XII. -XIV.). The entrances, how- 

 ever, are nearly all aggregated in a broad belt around the base. The 

 •average mounds studied by McCook were 2^ to 3 feet high, and he 

 mentions nests 12 and 15 feet across the top, and one, the largest ob- 

 served, 24 feet across the top, 58 feet around the base, and about 42 

 inches high. On Staten Island there are about a dozen of the nests in 

 a colony, but in Connecticut and Massachusetts I have found them 

 singly and often at long intervals. All of these facts indicate that the 

 species is in a decidedly more depauperate condition in these different 

 regions than near Hollidaysburg, where its nesting habits were stud- 

 ied by McCook. This author mentions colonies of these ants of as 

 many as 1800 mounds, and he describes the process by which new 

 hills are produced by a kind of nidamental budding or proliferation. 

 After the marriage flight "some of the fruitful females, it is known, 

 are seized by the workers upon the mounds and others upon the neigh- 

 boring grass-stalks and weeds, and are thence forced into the hill. 

 But there must be some who drop upon secluded spots, and unob- 

 served begin measures for the establishment of new families, accord- 

 ing to their instinct. These families eventually erect independent 

 hills, which in turn become the mother hills of new hill-clusters. Thus 

 ant colonies, like some groves and forests, grow from the parent stock 

 by shoots." 



This observation, together with others recorded in McCook's paper, 

 indicates that new nests of exsectoides may be formed like those of 

 F. rufa in Europe. In a former paper I have given my reasons for 

 believing that the exsectoides colony is originally started by temporary 

 parasitism on F. subsericea. Schmitt, Forel and myself have all found 

 small mixed colonies of these two species under circumstances which, 

 in the light of my observations on F. consocians, certainly justify such 

 an inference. Experiments with artifically dealated ievaaXes oi exsec- 

 toides introduced into small colonies of subsericea workers gave practi- 

 cally the same results as those above recorded for F. integra. In all 

 except one of seven experiments the results were negative, but they 

 revealed, nevertheless, some of the inquilinous instincts of the exsec- 

 toides female. Only three of the experiments are here recorded. 



