212 



PROTECTION AGAINST INSECTS. 



b. Life-history. 



Flight in June and July, in brilliant sunshine. 

 Eggs laid either singly or by twos and threes on the bark 

 of smooth saplings, especially at the base of stems exposed to 

 the sun. 



The larvae appear in August, and live over two winters before 



pupation, which takes place in 

 April or May of the third summer 

 in a pupal chamber made in the 

 sapwood or bast. 



The images emerge in June or 

 July, leaving a hole oval below 

 and straight above, thus : ~. 



Generation lasting two years ; 

 the insects seldom appear in large 

 numbers. 



c. Relations to the Forest. 



The beetle prefers young beech 

 plants, but also attacks alder, 

 birch, oak, and aspen, especially 

 weakly saplings, generally stand- 

 ing in the open, or along the edge 

 of the forest. It is, however, only 

 the larvae which are really de- 

 structive. They burrow through 

 the bark down to the sapwood, 

 and excavate in it a shallow, 

 well-defined winding passage, 

 sometimes extending deeper into 

 the wood ; it increases in breadth 



Figs. 80 and 81. Injury caused to 

 beech -saplings by A. viridis, L. 

 (Natural size.) 



a Larval gallery, exposed by removal 



of the bark. 

 b Old larval galleries exposed by 



rupture of the bark. 

 c Transverse oval flight-holes of the 



imago. 



with the age of the larvae. 



If the plant be girdled, the upper part of the stem dies, at 

 least in dry localities. The bark projects somewhat all along 

 the sides of the passage. In the case of saplings which 

 recover, the bark splits, owing to the pressure of the callus 

 forming over the wound. 



