PINE-BEETLE. 



267 



under a bark- 

 scale, and may 

 be marked by 

 ejected wood - 

 powder or by a 

 drop of tur- 

 pentine. The 

 larvae eat out 

 secondary gal- 

 leries in the 

 bast, which 

 branch out at 

 right angles to 

 the primary gal- 

 lery, soon be- 

 coming wide, 

 irregular and 

 confluent. They 

 only graze the 

 sapwood. The 

 pupae and im- 

 mature beetles 

 are embedded in 

 the bark, near 

 its outer surface. 

 The second 

 and most serious 

 form of damage 

 is done to the 

 young shoots. 

 The newly-dis- 

 closed beetles 

 of the first or 

 second broods, 

 in August and 

 September, bore 

 into the pith of 

 young pine - 

 shoots at a 



Fig. 126. Burrows of M.piniperda, L., in pine-bark. 



(Natural size.) 



a Characteristic angle near the beginning of the mother- 

 gallery. 



b Larval gallery free of wood-dust. 

 c Larval gallery full of wood-dust. 

 d Air-passages. 



