276 



PROTECTION AGAINST INSPXTS. 



pf^'?™^'''rTli7Tr^WlJfJi 



the beginning of April, and again in Octol)ei-. "When pairing 

 takes place late in the spring (May and June) the generation 

 is only single. 



c. llcJalions io Ihe Forest. 



This beetle attacks the ash almost exclusively, and prefers 

 large trees with fissured bark. The female makes short, 

 slightly bent, generally two-armed 

 galleries. The two arms are gene- 

 rally of unequal length and inclined 

 at an acute angle ; sometimes only 

 one is present. The larval burrows 

 run at first upwards or downwards, 

 that is, at right angles to the 

 mother-galleries, gradually curving 

 and becoming horizontal ; they are 

 of great length, and are often 

 abruptly bent on themselves once or 

 twice in their course. Fig. 135 

 shows the appearance of a gallery, 

 in which boring beetles as well as 

 larvae may be distinguished ; the 

 latter so closely packed that their 

 galleries have coalesced. It is, 

 however, hardly typical of the 

 species. If the ? do not lay, they 

 bore simple tunnels, frequently just 

 under the outermost bark, which 

 then generally splits and flakes oflf 

 over the point of attack. Excep- 

 tionally the beetle has been found 

 attacking old oak-trees in the Russian Chersonese; the 

 galleries in this case may be three-armed. 



The attacks of this insect may be treated as for ILj'vaxbn. 



Fig. 13u. — Burrows of II. ci-cnu' 

 Ins, iu ash bark. 

 a Eutrauce-liole. 

 b Mother-galleries. 

 c iJeethis excavating g 

 d Boriu"- larvae. 



.lie 



C SUBFAJIILY SCOLYTINI. 



Description of Siihjitinilij. 

 This sub-family contaiiis a single genus, Scolytas, the 

 species of which possess a projecting head with a short, broad 



