INDIRECT INJURIES CAUSED BY INSECTS. 235 



attempt, can divert them from it. Numerous are the 

 tribes of insects that seek their food in our timber, 

 whether laid up in store for our future use, employed in 

 our houses, buildings, gates or fences, or made up into 

 furniture. The several species of Mr. Marsham's ge- 

 nus Ips (which includes the coleopterous genera Apate, 

 Bostrickus, Hylessinus, Hylurgus, Tomicus, Platypus, 

 Scolytus, and Phloiotribus of modern systematists) all 

 prey upon timber, feeding between the bark and the 

 wood, and many of them excavating curious pinnated 

 labyrinths. Almost every kind of tree has a species of 

 this genus appropriated to it, and some have more than 

 one a . The Stag-beetle tribe, or Litcanidtz, and several 

 of the weevils b , have a similar appetite, but penetrate 

 deeper into the wood. The most extensive family, how- 

 ever, of timber-borers are the Capricorn beetles, includ- 

 ing the Fabrician genera of Prionus^ Cerambyx^ Lamia c , 

 StenocoruS) Calopus, Rhagium, Gnoma, Saperda, Calli- 

 dium, and Clytus. The larva of these, as soon as hatched, 

 leaves its first station between the bark and wood, and 

 begins to make its way into the solid timber, (some of 

 them plunging even into the iron heart of the oak, and 

 one even perforating lead d ,) where it eats for itself tor- 



a Kirby in Linn. Tram. v. 250. 



b Curculio Hgnarius, Marsh. Rhinosimus nificollis, Latr. 



c The species of the genus Dorcadion separated from Lamia are 

 discovered to live upon the roots of grass. 



d The larva of a Callidium (which Dr. Leach has discovered to be 

 C. Bajulus) sometimes does material injury to the wood-work of the 

 roofs of houses in London, piercing in every direction the fir-rafters, 

 and, when arrived at the perfect state, making its way out even 

 through sheets of lead one-sixth of an inch thick, when they happen 

 to have been nailed upon the rafter in which it has assumed its final 

 metamorphosis. I am indebted to the kindness of Sir Joseph Banks 

 for a specimen of such a sheet of lead, which, though only eight inches 



