ants' nests. 355 



nest always lies under the superstructure of the mound-building 

 ants. 



What purpose does the latter serve ? Judging from my own 

 observations, the same purpose as the stones — to wit, to procure 

 warmth for the brood. The grass springs up in May, and with it 

 the ant mounds. These afford protection against the dampness 

 and the shade of the primeval forest ; for such is a meadow to the 

 ants. Up there, under the roof of the mound, the rays of the 

 sun are felt. We have in Europe a small ant ( Tapinoma erraticuin 

 Latr.), whose perishable earth structures, first described by me, 

 can, to all appearance, serve no other purpose. It builds hastily 

 around the blades of grass a comparatively very high and steep 

 mound of earth, which consists of little more than the upper, 

 superficial, thin vault. Inside there are often only a few wretched 

 thin chambers, especially where the grass is thick. The ants hold 

 their brood partly in their upper jaws, partly lay them on leaves. 

 They crowd together under the mound to warm themselves in 

 the rays of the sun. After the harvest the mounds of the Tapi- 

 noma disappear, while those of the other ants remain standing. 

 The latter, however, also become more and more flattened as 

 autumn approaches. Our Fig. 12 represents the perpendicular 

 cross section of a nest of Tapinoma enaticum^ Latr., from Vaux, 

 Canton Vaud, Switzerland, which was strengthened and preserved 

 by me by means of a solution of silica, and is now in the Ento- 

 mological Museum of the Federal Polytechnikum. Mr. L. 

 Schroter has drawn the nest two-thirds of the natural size. Z>, 

 the temporary earthen cupola ; Mm, the beginning of the under- 

 ground mined structure. 



Among us mounds of earth with labyrinths are built by all the 

 species of Lasius, with the exception of Lasius fultginosus, Ltr., 

 hrunneus, Ttr., and emarginatus^ 01. ; also by Tetramoriwn ccespi- 

 ttim, the species of Myrmica, several of Formica and Campojwtus^ 

 and the 'species of Tapinoma ; and in Tunis by Monotnorium 

 saiomonis, Aphcenogaster striola^ sardoa, testaceopilosa^ crocea, etc. 

 The best artist is the most common of all ants, Lasius nigcr, L., 

 which swarms in all our gardens. This ant also constructs covered 

 passages along the stalks of plants, where in this way it walls up 

 its plant lice and cochineal kermes in artistic stalls. The species 



