268 



PROTECTION AGAINST INSECTS. 



Fig. 127. Pine-bark with cham- 

 bers (), pupae (b) and images (c) 

 M. piniperda, L. 

 (Natural size.) 



distance of 1 to 3 in. from their extremities, choosing 



especially those of sickly or old 

 trees, in preference on sunny 

 borders of woods ; they eat out 

 a burrow about an inch long, 

 working upwards to the buds. 

 The entrance - holes into these 

 shoots are surrounded by a 

 whitish ring of resin. The beetle 

 leaves the hollowed - out shoot 

 either by the original bore-hole 

 or by a fresh hole made at the 

 end of the burrow, and recom- 

 mences his destructive work in 

 another shoot. In these galleries 

 excrement is never found, and 

 thus the action of M.piniperda,Ii. t 

 may be distinguished from that 

 of Tortrix biioliaua, Schiff., the 

 caterpillar of which also bores out 

 Scots pine shoots, but always 

 leaves excrement in the borings. 

 Weak side-shoots which have been 

 bored break off generally at the 

 bore-hole, and fall to the ground. 

 Stronger shoots from the crown 

 develop the suppressed buds be- 

 tween the pairs of needles, which 

 with favourable spring - weather 

 grow into short needles, and give 

 the shoots a bushy appearance. 

 The height, growth and develop- 

 ment of the crown are thus 

 seriously affected ; and the pro- 



Fig. 128. Pine-shoot, hollowed , ,. , . . n 



out by M. pimped, L., with ductlon of cones bein g materially 

 two beetle-holes. reduced greatly impairs the success 



of natural regeneration of Scots 



pine forests. Fig. 128 shows a hollowed-out twig bearing 

 a cone. Such twigs may be found lying on the ground 



