356 ants' nests. 



of Myrmica frequently build earthen stalls around the plant lice 

 on the stalks of plants without putting them in communication 

 with the ant-hill by a covered way. 



In the island of St. Thomas I saw earthen structures made by 

 Solenopsis geminata^ F. In Australia the large species of the 

 genus Myrmica, which are 20 to 28 millimetres long, build 

 immense nests of earth. 



A seed -harvesting ant in Colorado, Pogonoinyrmex occidentalism 

 Cresson, builds a very peculiar and isolated variety of the earthen 

 mounds. It plasters or paves the whole upper surface of its 

 earthen mound uniformly and in mosaic with a layer of small 

 white stones, which, according to McCook's observations, it 

 frequently brings from a great depth in the ground. The still 

 unknown object of this paving is probably the same as that of the 

 earthen mounds in general. It is extraordinary that the little 

 paving stones are placed side by side with great regularity like a 

 street pavement, while the interior of the cupola contains no stones 

 whatever. McCook has even seen upon these mounds stones 

 containing fossil remains and native gold. Mr. Henry de Saussure, 

 of Geneva, made similar observations before McCook among the 

 genuine Pogonomyrmex barbatus, i. sp.. Smith, but did not publish 

 them. 



3. — Wood Nests. 



There are also woodcutters among the ants, and in not a few 

 cases the same species knows how to make earthen structures and 

 how to hollow out wood, as, for instance, our Camponotus ligni- 

 pci'dus, Latr. 



The best woodcutters are those species of the genus Caitipono- 

 tus, Mayr, which have a short, broad head, rounded off in front, 

 especially the sub-genus Colobopsis, Mayr. 



These ants frequently bore with their short, powerful jaws into 

 the very hardest wood, and construct secure and elegant labyrinths 

 for themselves in it. This is the case with Camponotus pubescois 

 in Wallis and Tessin, and Camponotus marginatus. The latter 

 bores into the softer layers of the wood when they are somewhat 

 decayed and lets the harder part remain, so that its nests are more 

 concentric around the centre of the bough or trunk in their 



