INDIRECT INJURIES CAUSED BY INSECTS. 209 



the enormous wens, and other monstrosities and defor- 

 mities observable in trees, may have been originally pro- 

 duced by the bite or incision of insects. 



Besides exterior insect enemies, living trees are liable 

 to the ravages of many that are interior. The caterpil- 

 lar of the great goat moth Cossus (ligniperda, K), of the 

 hornet hawk-moth (Sesia crabroniformis, F.), and of two 

 beetles (Nitidula grisea, F., and Curculio Lapathi, L.), 

 devour the wood of the willow and sallow, which thus in 

 time often become so hollow as to be easily blown down. 

 The bee hawk-moth (Sesia apiformis^ F. a ), and probably 

 Rynchites Popidi, a brilliant green weevil, feeds upon the 

 poplar — Prionus coriarius is sometimes found in the oak 

 and sometimes in the elm, and Bostrichus Pini, F. in 

 the Scotch fir. Mr. Stephens informs me that the fir- 

 trees in a plantation of Mr. Foljambe's in Yorkshire were 

 destroyed by a hymenopterous insect (Sir ex Gigas, L.), 

 while those of another belonging to the same gentleman 

 in Wiltshire met with a similar fate from the attack of 

 Sirex Juvencus, L. — When the sap flows from wounds in 

 a tree it is attended by various other beetles, (I have 

 observed Cetonia aurata, F., and several Nitidulce and 

 Staphylinidce busy in this way,) which prevent it from 

 healing so soon as it would otherwise do; and if the 

 bark be any where separated from the wood, a numerous 

 arnry of wood-lice, earwigs, spiders, field-bugs, and si- 

 milar subcortical insects take their station there and 

 prevent a re-union. 



The mischief however produced by any or all of these, 

 is not to be compared with that sometimes sustained in 



a Lewin in Linn. Trans, iii. 1. — Curtis in do. i. 86. 

 VOL. I. P 



