PINE BEETLE. 



243 



The great mischief is caused by the beetles after they have 

 left the breeding galleries beneath the bark ; then they are 

 sometimes very destructive, and especially to young Pine 

 plantations, by boring through the side of the tender shoots 

 and eating their way for an inch or two or more along the 

 pith. The injury to side shoots by this means is considerable, 

 but in the case of the leading shoot being thus lost the tree 

 often becomes bushy-headed, its growth is retarded, and its 

 ultimate value is reduced. 



The Pine Beetles are of the size figured (p. 242), and of the 

 shape given more clearly in the magnified figure, of a pitchy 

 colour when mature, but paler previously, rough, punctured, 

 with longish hairs, and furnished with strong jaws. The wing- 

 cases are rounded down at the sides, and cover a pair of wings 

 capable of strong flight. 



The female appears in April or May, and begins her opera- 

 tions by boring a hole through the bark, beneath which she 

 forms a gallery or tunnel of a little more than her own width ; 



Tunnellinga of Pine Beetle. 



along each side of this she lays her eggs, from which the larvse 

 or maggots soon hatch, and each larva eats its way forward 

 beneath the bark, thus forming a series of burrows, gradually 

 getting larger towards the extremities, sometimes running 

 nearly at right angles with the first (or mother beetle's) tunnel, 

 at others bending in various directions, as here figured. The 

 burrows are eaten out of the under side of the bark, but often 

 show just a trace of working on the outside of the wood lying 

 against it. The above figure shows one mother gallery, with 



e2 



