ants' nests. 483 



which mine only in this way, as, for example, Ponera contractu Ltr., 

 Myrmecocystus, all the Dorylides, Aphamogaster snhterranea Ltr., and, 

 in general, most of the blind and half-blind species. Besides these 

 many other species do it occasionally, such as Formica fasca L., Formica 

 rufibarhis F., Tetramorium cwspitum L., species of j\lyrmica, etc. 



One variety of the mined nests consists of those in which the ants 

 heaj) up the excavated earth in banks around the openings of the nest 

 so that crater-shaped openings are the result. This occurs most fre- 

 quently in sandy soil. These banks are not genuine upper structures, 

 although they often resemble them closely. We iind them in the case 

 of Messor ,structor, Messor harbarus, species of Pheidole, Acantholepis 

 frauenfcldi, Pogonomyrmex^ etc. A peculiar variety of this class is 

 formed by the crescent-shaped mounds of Messor arenarius Fab., first 

 noticed by me in the Sontli Tunis desert near Cabes, which consist of 

 coarse but very perishable globes of sand. At certain times the aper- 

 tures of the Messor nests are, in addition, surrounded by mounds com- 

 posed of the hulls of the seeds which have been gathered, wliich hulls 

 have been thrown out of the nests. The little Cardiocondyla elegans 

 Em. and stambuloffii Forel make small nests in the sand on the 

 seashore. 



The subterranean structures of some kinds of ants are, in certain 

 cases, extremely interesting. Certain species dig passages which go 

 down very deep and branch off laterally, forming subterranean cor- 

 ridors, and in many cases leading to root i)lant lice {Lasius faviis) or 

 serving for other purposes. The underground hunts of the species of 

 Dorylus, or visiting ants, are partially carried on in this manner. These 

 are blind robber ants, which carry on an underground hunt after all 

 conceivable ground insects, as I myself have observed in Tunis. They 

 are also called "visiting ants," because they frequently make a sud- 

 den attack at night upon dwelling houses and destroy all the vermin 

 in them. 



The species of Messor (Europe), Pogonomyrmex (America), and Hol- 

 comyrmcx (India) construct under ground, at a considerable depth 

 (often at the depth of a yard), very large chambers or granaries, in 

 which they store the seeds which they have gathered. In the same 

 way the species of the American genus Atta excavate extremely deep 

 and extensive -passages and make immense chambers, in which they 

 store the leaves which they have cut from trees, in order to lay oft" upon 

 them the fungus gardens from which they supply themselves with food- 

 This discovery, which was first made by Belt and subsequently declared 

 by MacCook to be incorrect, has been recently confirmed by Dr. 

 Moller, of Blumenau, in its full extent and by superb exi)eriments. 



A great deal of interest is likewise attached to the underground 

 hunts carried on by the ants of the genus Lobopelta in India, after the 

 termites, according to the careful observations of Mr. Wroughton. 

 They feed upon these white ants, and pursue them in their own pas- 



