138 



HYMENOPTERA 



terranean mining. Their systems of tunnels and nests are known 

 to extend through many square yards of earth, and it is said on 

 the authority of Hamlet Clark that one species tunnelled under 

 the bed of the river Parahyba at a spot where it was as broad 

 as the Thames at London Bridge. 



A considerable number of ants, instead of mining in the 

 ground, form chambers in wood ; these are usually very close to 

 one another, because, the space being limited, galleries cannot be 

 indulged in. Oamponotus ligniperdus in Europe, and C. pennsyl- 

 vanicus in North America, work in this way. 



Our British Lasius fuliginosus lives in decayed wood. Its 

 chambers are said by Forel to consist of a paper-like substance 

 made from small fragments of wood. Cryptocerus burrows in 



branches. Cdobopsis lives in a 

 similar manner, and Forel in- 

 forms us that a worker with 

 a large head is kept stationed 

 within the entrance, its great head 

 acting as a stopper ; when it sees 

 a nest-fellow desirous of entering 

 the nest, this animated and intel- 

 ligent front-door then retreats a 

 little so as to make room for 

 ingress of the friend. Forel has 

 observed that in the tropics of 

 America a large number of species 

 of ants live in the stems of grass. 

 There is also quite a fauna of 

 ants dwelling in hollow thorns, 

 in spines, on trees or bushes, or 

 in dried parts of pithy plants ; 

 and the tropics also furnish a 

 number of species that make nests 

 of delicate paper, or that spin 

 together by means of silk the 

 leaves of trees. One eastern 

 species Polyrliachis spinigera fabricates a gauze-like web of 

 silk, with which it lines a subterranean chamber after the 

 manner of a trap-door spider. 



Some species of ants appear to find both food and shelter 



FIG. 59. Ant-plant, Hyclnophytum mon- 

 tanum. Java. (After Forel.) 



