356 



PROTECTION AGAINST INSECTS. 



lining it with a glazed coating. The wood-wasp emerges in 

 July, by a larval-gallery, or by boring- for itself a short way 

 through the wood. The flight-hole is circular (being thus 

 distinguished from those of longicorn beetles that are oval), and 



Fig. 185. Pine-wood bored by the larva of Sirex jnvencus, L. (Natural stzc.~) 

 a Larval burrows partly filled with boring-dust ft. 7 Circular flight-hole. 



about the fourth of an inch in diameter. The generation lasts 

 at least two years, and sometimes longer, the wasps appearing 

 from wood which has been worked up for some time. 



In Germany, it sometimes attacks spruce as well as Scots 

 pine, and in the British Isles* it has been observed on larch, 



* Miss Ormcrod, ojt. cit , page 209. 



