336 Philippine Journal of Science imb 



Table V. — Incubation period of eggs of Coptotermes formosanus. 



RECORDS FOR 1915. 



Days. 



Caaee. 



25 1 



26 1 



27 2 

 30 1 



RECORDS FOR 1918. 



24 1 



26 4 



27 7 



28 5 



29 3 



30 5 



31 5 



32 4 



In infesting buildings it generally gains entrance from out- 

 door colonies. By means of subterranean tunnels of consid- 

 erable length, which originate from a nest in the ground, it 

 reaches the foundation of a building. At first it attacks founda- 

 tion timbers, flooring, or supports of porches or steps that are 

 in contact with the ground, and gradually extends its tunnels 

 and excavation into the first, the second, or even the third 

 floor and into the roof, passing through the walls or the interior 

 of timbers (Plate VI, fig. 1). 



In cases where the foundation is of stone, concrete, or other 

 impermeable material, it constructs a covered tunnel of a mixture 

 of earth and saliva over the surface and reaches the woodwork. 

 Generally a cross section of this artificial tunnel is semicircular, 

 the diameter being from 5 to 10 millimeters (Plate VII, fig. 1). 



Damage to buildings. — Ordinary Japanese houses are chiefly 

 constructed of wood and clay, the foundation timbers being laid 

 in contact with the ground. Thus the construction itself is not 

 fitted to prevent the attack of termites. Moreover, Japanese 

 pine and cryptomeria, which are most liable to be attacked by 

 Coptotermes formosanus, are the principal building materials. 

 Such being the case, the Japanese people suffer a great deal 

 from the damage when they erect buildings of their own style 

 in Formosa. 



As the work of Coptotermes formosanus is hidden, it is dif- 

 ficult to detect the presence of the insects or the damage that 

 they are doing. After they have caused the fall of a building, 

 the beams, the rafters, and other important parts of the wood- 

 work are often found to be mere shells, the interior being en- 

 tirely honeycombed (Plates V and VI). 



