152 



NATURAL HISTORY. 



commits his ravages beneath the surface, and a timber apparently sound 

 to superficial examination may be tunnelled in every direction by its 



tubes ; the gribble, on the other hand, is confined to 

 t lie surface, and one can see at a glance how far the 

 destruction has gone on. The gribble is widely dis- 

 tributed ; on our east coast, for some unknown reason, 

 its damages are comparatively inconsiderable, but in 

 \ Europe and on our Pacific coast it is a serious pest. 

 Chving to its ravages the long wharves of the Central 

 Pacific Railroad at Oakland, Cal., require constant alter- 

 ation and renewal, while across the bay at San Fran- 

 cisco it plays similar havoc with the piers. Various 



FiG.i3o.-Gribbie(L*-m- attem P ts nay e been made to check the damage, and 

 norta^iigwrum), en- i t j ias been f ound that if t i mDe r be impregnated with 



creosote introduced under pressure, it will be protected 



to a considerable extent. 



Others of the fourteen-footed forms live the lives of parasites. One 



form known to the fishermen as the ' fish-louse ' 

 takes up its residence just inside the jaws of 

 the menhaden, where, with its sharp claws it 

 holds firmly to the roof of the mouth and sam- 

 ples all the food of its host even before the fish 

 has had an opportunity to taste it. Mr. Latrobe, 

 who first noticed this peculiarity of habitat, re- 

 called the old tasters or prcegustators of the Roman 

 emperors, whose duty it was to taste every dish, 

 so that their master should not be poisoned ; and 

 so to-day this fish-louse figures as Cymothoa prce- 

 gustator. "The fishermen say the fish-louse is 

 necessary to the life of the fish, and as a proof of 

 it they observe that if the louse be taken from him, 

 the fish will die, although thrown into the water ; 

 but it is probable that the death of the fish is not 

 owing to the removal of the parasite, but to its 

 being withheld too long from the water, as it is 

 well known that this fish lives but a very short 

 time when taken from the water." 



In its general appearance the salve-bug, as 

 the fishermen call it, is much like the preceding 

 species. It is frequently found adhering to the 



skm of cod and haddock, and occasionally to other fish. It is the largest 



Fig. 136.— A ' fish-louse ' or 'salve 

 bug' (JSga). 



