44 WHEELER. [VOL. II. 



bacteriologists for growing cultures of micro-organisms. The 

 ants are hastily scooped up, together with their larvae, pupae, 

 and much of the earth in which they have excavated their nest, 

 and the whole is transferred to a Petri dish. One or two glass 

 slides are then placed on the earth, which is spread out till it 

 forms a layer not more than about 5 mm. in thickness. The 

 Petri dish is kept covered to retain the moisture in the soil. 

 In the course of a day or two the ants excavate rough-walled 

 chambers under the slide and galleries in the adjacent soil, of 

 the same size and shape as those which they are in the habit 

 of forming in their natural nests. They also gather their eggs, 

 larvae, and pupae into these chambers, where they may be easily 

 seen. When the slides become smeared or covered with earth 

 they can at any time be hastily replaced by clean ones without 

 greatly disturbing the ants. 



The Ponerinae may appear to lead very monotonous lives to 

 any one who has kept under observation the different species 

 of Myrmica, Pogonomyrmex, Lasins, Camponotus, and Formica. 

 But this very monotony is full of interest to the observer who 

 sees in the rudimental activities of these ants a certain picture, 

 however imperfect, of the simple stages through which the 

 higher ants have passed in attaining to their present remark- 

 ably differentiated social organizations. It can hardly be 

 doubted that there is a phylogeny of instincts, as there is a 

 phylogeny of structures, and there is certainly no single ani- 

 mal group which more clearly illustrates the truth of this 

 statement than the Formicidae. 



PONERA COARCTATA LATREILLE. 



Our American P. coarctata is considered by Emery 1 to differ 

 sufficiently from the European form to be ranked as a sub- 

 species, which he calls pennsylvanica Buckley. In the worker 

 the single node forming the pedicel of the abdomen is some- 

 what thicker and much broader behind and less narrowed 

 anteriorly than in the European forms. The punctation of 



1 " I'.eitrage zur Kenntniss der nordamerikanischen Ameisenfauna " (Schluss), 

 Zool. Jahrb. Abth. f. System. Ed. viii, pp. 257-360, Taf. VIII. 1894. 



