1901.] NATURAL SCIENCES OF PHILADELPHIA. 425 



A STUDY OF AN ANT. 

 BY ADELE M. FIELDE. 



The colonies of Stenamma (Ajyhoinogaster) fulvum Mayr, sub- 

 species aquira Buckley, variety piceum Emery, a jNIyrmicid ant 

 found commonly in the neighborhood of Wood's Hole have varied 

 in the numbers of their inmates from a few individuals to many 

 thousands. The nests are near the surface, in mellow soil, by 

 roadsides, in meadows, and in woods, and are usually neai', among, 

 or under loose stones.^ 



^ Unless otherwise iudicated the ants under observation were kept in the 

 portable nests described by the author in Vol. 2, No. 2, of the Biological 

 Bulletin. The species mentioned in this paper were identified for the 

 writer by Prof. William Morton Wheeler, of the University of Texas. 

 The colonies under inspection were kept at the Marine Biological Labora- 

 tory at Wood's Hole, Mass., from July to the end of September, 1900, 

 and in New York City from then until the first of June, 1901, when 

 they were carried back to Wood's Hole. The temperature of the room 

 in which they were kept in New York varied from 40^ to 90 J F., or 5^ 

 to So-' C, and this variation often occurred during single days. The 

 word day is used thronghout this narrative as representing a period of 

 twenty-four hours' duration. The use of Petri double-dishes in the study of 

 living ants was suggested to the author by Prof. Wheeler. Those referred 

 to in this study were about 100 millimeters in diameter and 10 ram. deep on 

 the inside. The cell formed by the double dish was set upon a disk of card- 

 board, covered with white Turkish towelling, to which a tiny patch of black 

 silk was attached. The Petri cell was set upon this disk, which was wider 

 than itself, and the cell was covered with another disk of thick dark blotting 

 paper. Within the cell were two sections of very fine-meshed sponge about 

 6 mm. thick, covering one-third the floor of the cell, and so placed as to leave 

 a passageway for the ants between the sponge and the cell-wall, and also a 

 triangular space where the ants could settle between the sponges and above 

 the black patch. The sponges were kept saturated with water, to give drink 

 to the ants and moisture to the air, and to prevent the hiding of the eggs in 

 the interstices of the sponge. Care was taken that the sponges should not 

 overflow and inundate the young. 



Particles of food, from three to six kinds, known to be acceptable to the 

 ants, were constantly provided, and laid on that part of the floor farthest 

 from the sponges. The air, the water, and the food were kept always fresh 

 and clean. The sponges were dipped in alcohol and well rinsed once a 

 week. 



The cells were set upon the shelves of a dark, well-aired cupboard, with the 

 food-side of the cell toward the source of light. Not more than seven ants 

 were permanently housed in a single cell. Among the ants kept several 

 months in this manner there were scarcely any deaths from natural causes. 



