INDIRECT INJURIES CAUSED BY INSECTS. 203 



The Linnean order Aptera furnishes another timber-eating 

 insect, a kind of wood-louse {Limnoria terebrans of Dr. Leach), 

 which though scarcely an eighth of the size of the common 

 one in point of rapidity of execution seems to surpass all 

 its European brethren, and in many cases may be productive 

 of more serious injury than any of them, since it attacks the 

 wood-work of piers and jetties constructed in salt water, and 

 so effectually as to threaten the rapid destruction of those in 

 which it has established itself. In December, 1815, I was fa- 

 voured by Charles Lutwidge, Esq. of Hull, with specimens of 

 wood from the piers at Bridlington Quay, which wofully con- 

 firm the fears entertained of their total ruin by the hosts of 

 these pigmy assailants that have made good a lodgement in 

 them, and which, though not so big as a grain of rice, ply 

 their masticatory organs with such assiduity as to have re- 

 duced great part of the wood-work which constitutes their 

 food into a state resembling honeycomb. One specimen was 

 a portion of a three-inch fir plank nailed to the North Pier 

 about three years before, which is crumbled away to less than 

 an inch in thickness — in fact, deducting the space occupied 

 by the cells which cover both surfaces as closely as possible, 

 barely half an inch of solid wood is left ; and though its pro- 

 gress is slower in oak, that wood is equally liable to be at- 

 tacked by it.^ If this insect were easily introduced to new 

 stations, it might soon prove as destructive to our jetties as 

 the Teredo navalis to those of Holland, and induce the ne- 

 cessity of substituting stone for wood universally, whatever 

 the expense: but happily it seems endowed with very limited 

 powers of migration ; for, though it has spread along both 

 the South and East Piers of Bridlington harbour, it has not 

 yet, as Mr. Lutwidge informs me, reached the dolphin nor an 

 insulated jetty within the harbour. No other remedy against 

 its attacks is known than that of keeping the v/ood free from 

 salt water for three or four days, in which case it dies ; but 

 this method, it is obvious, can be rarely applicable.^ 



1 See the elaborate memoir of Mr. Coldstream in Edin. New Phil. Journ. 

 April, 1834 ; remarks on this insect by the Rev. F. W. Hope in Trans. Eyit. Soc. 

 Lond. i. 119. ; also by Dr. Moore, in Mag. of Nat. Hist. N. S. ii. 206., who states 

 that its injurious effects have been known at least forty years in the harbour at 

 Plymouth, whei*e It is called the " gribble. " 



2 In order to ascertain how far pure sea water is essential to this insect, and 



