64 OF WOOD EST GENERAL 



On the other hand, creosottng is by no means always sufficient to 

 keep of! their attacks. Shipworms occur in all seas : they gene- 

 rally bore with the grain, Hning their burrows with a layer of 

 calcareous matter, and carefully avoiding one another's burrows. 

 They will sometimes completely riddle timber within four or five 

 years. In Australia they are known as *' cobra." 



The termites belong to the Neuroptera, an entirely distinct 

 Order of the insect class from that to which the true ants belong. 

 They occur in a great variety of species throughout the Tropics, 

 but especially in South America, hving in societies of prodigious 

 numbers, and, no doubt, fulfilhng a useful function in the economy 

 of nature, by disintegrating, removing, and destroying wood that 

 is already decayed, just as the ship-worms rid the seas of much 

 derelict timber. The termites will, however, attack most species 

 of wood after conversion, sometimes eating their way upward 

 from the foundations of a house to its rafters until all its timbers 

 are reduced to a mere shell, or completely destroying wooden 

 articles of furniture. The pungent resinous secretions which repel 

 the teredo seem also generally effective as a protection against 

 termites. 



The large and voracious larvae of some moths are most destruc- 

 tive to growing trees, and sometimes attack converted timbers. 

 Very generally their eggs are laid in the bark, and the grubs 

 generally bore downward through the sapwood. The Goat-moth 

 {Oossus Ugniperda), for instance, specially attacks aged and already 

 unsound Willows, Ash, Elm, Cork Oak, etc. ; but will attack 

 converted as well as Hving wood. The Wood-leopard {Zeuzera 

 CBSCuli) specially attacks living fruit-trees and Horse-chestnuts, 

 and its AustraHan congener, the Wattle Goat-moth {Z. eucalypti), fre- 

 quents the various species of Acacia. Such insects are most destruc- 

 tive ; but their large galleries are only too obvious in converting 

 timber. Of the wood-boring beetles, on the other hand, many only 

 attack unhealthy trees : others, such as Scolytus destructor, the Elm- 

 bark beetle, tunnel in and under the bark, especially of fallen logs, 

 only occasionally penetrating a small depth into the outer wood. 

 Others are far more destructive, in many cases mainly attacking 

 sound converted timber. The widespread Death-watch beetles, 

 for instance (Anohium domesticum, A, tessellatum, and allied forms), 

 the chief cause in England of the familiar " worm-holes " in Oak, 

 frequently entirely destroy the timbering of roofs, and still more 

 commonly riddle our smaller articles of furniture. In the Tropics 

 and warmer Temperate regions their place is largely taken by the 

 numerous family Bostrychidce, some of which attain far larger 

 dimensions. 



