138 PROTECTION OF WOODLANDS. 



felled stems or windfall trees ; but, failing such, it also attacks 

 standing timber at a considerable height above the ground, 

 invariably selecting stems of large girth, and in these the portions 

 having thick bark. The sunny edges of compartments, and the 

 warm sides of trees surrounding small blank areas, are therefore 

 its favourite breeding-places, a fact which should be kept in mind 

 when felling and placing decoy-stems. From the copulating 

 chamber, which is somewhat large, a vertical gallery is hollowed 

 out to a length of up to 6 inches, mostly either proceeding up or 

 down the stem parallel to its axis, though it less frequently also 

 occurs that there are two such longitudinal galleries running 

 closely parallel to each other ; these main galleries have 2 to 5 air- 

 holes as well as the entrance-hole, and hardly touch the sapwood. 



In small indentations made alternately on the right and left 

 sides, and somewhat close to each other, the female, within a few 

 weeks, deposits from 30 to 50 eggs, and sometimes many more 

 (to about 100 it has been asserted), fixing them into position 

 in the dents with glucose substance. About fourteen days later 

 the larvae creep out of the shells, and begin to eat their way side- 

 wards from the main gallery, forming sinuous larval galleries at 

 right-angles to it at first, which gradually get broader and bite 

 deeper into the cambial layer till they attain from 2 to 4 inches 

 in length, each terminating with the pupal chamber, in which the 

 chrysalis stage is passed. After a pupal rest of 8 days, the 

 chrysalis develops into the beetle, at first of a bright yellow 

 colour, but quickly becoming darker in appearance, which sooner 

 or later, according to the state of the weather, makes its exit 

 from the stem by a circular hole. The whole of the metamor- 

 phoses from Ovum to Imago occupies 8 weeks on the average, 

 but can take about 12 weeks under less favourable circum- 

 stances. 



The first generation of beetles swarms from the middle of June 

 till July, and at once reproduces itself in a new brood, which is 

 also fully developed by autumn, either hibernating as beetles 

 before reproducing themselves, or else under particularly favour- 

 able circumstances, (as, for instance, if they swarm as early as 

 August), proceeding at once to reproduce a third generation within 

 the year. From this it will be seen how enormously this insect 

 can multiply under favourable circumstances ; but fortunately, in 

 the rawer mountainous tracts, where it naturally occurs most fi 



