212 INDIRECT INJURIES CAUSED EY INSECTS. 



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^), and probably 

 RyncJiites Pojmli, a brilliant green weevil, feeds upon the 

 poplar — Prioniis coriarius is sometimes found in the oak 

 and sometimes in the elm, and Hylurgus piniperda ^, 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 [Sirex Gigas), 

 while those of another belonging to the same gentleman 

 in Wiltshire met with a similar fate from the attack of 

 Sii-ex Juvencus. The elm also suffers dreadfully from the 

 attack of another minute beetle {Scolytus destructor)^ re- 

 lated to the last '^. — When the sap flows from wounds in 

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

 served Cetonia aurata, and several Nitidulce and Bra- 

 chyptera 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 army of 

 wood-lice, earwigs, spiders, field- bugs, and similar sub- 

 cortical 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 

 Germany from the attacks of a small beetle, [Bostrichis 

 Typographus) so called on account of a fancied resem- 

 blance between the paths it erodes and letters, wl^iich 

 bores into the fir. This insect, in its preparatory state, 

 feeds upon the soft inner bark only : but it attacks this 



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

 ^ Curtis Brit. Ent.t. 104. 



' MacLcay in Edinburgh Pkilos. Jonrn. n. xxi. 123. Curtis Biit. 

 Ent. t. 43. 



