INDIRECT INJURIES CAUSED BY INSECTS. 243 



worse plao^ue than either of these insects — they are the 

 great calamity, as Linne terms them, of both the Indies. 

 When they find their way into houses or warehouses, 

 nothing- less hard than metal or glass escapes their ra- 

 vages. Their favourite food, however, is wood of all 

 kinds, except the teak ( Tectona grondis) and iron-wood 

 {Sideroxi/lon), which are the only sorts known that 

 they will not touch ^; and so infinite are the multitudes 

 of the assailants, and such is the excellence of their 

 tools, that all the timber- work of a spacious apartment 

 is often destroyed by them in a few nights. Exteriorly, 

 however, every thing appears as if untouched ; for these 

 wary depredators, and this is what constitutes the 

 greatest singularity of their history, carry on all their 

 operations by sap and mine, destroying first the inside 

 of solid substances, and scarcely ever attacking their 

 outside, until first they have concealed it and their ope- 

 rations with a coat of clay. A general similarity runs 

 through the proceedings of the whole tribe ; but the 

 large African species, called by Smeathman Termes 

 hellicosus, is the most formida])le. These insects live in 

 large clay nests, from whence they excavate tunnels all 

 round, often to the extent of several hundred feet ; from 

 these they will descend a considerable depth below 

 the foundation of a house, and rise again through the 



* It is not ils hardness that protects the teak, as the Asiatic Termites 

 attack Lignum Vitse, hut probably some essential oil disagreeable to 

 them with which it is impregnated. This is the more likely, since they 

 ■will eat it when it is old and has been long exposed to the air. Tannin 

 has been conjectured to be the protecting substance, but erroneously, as 

 leather of every kind is devoured by them. Williamson's East India Fade 

 Mecum, ii. 56. It is its hardness probably that protects the iron-wood 

 from the African Termites. Smeathman in Philos. Trans. IT81. 11. 4T. 



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