282 



FOREST ENTOMOLOGY. 



insect, and the conspicuousness of the damage, the injury is often 

 attributed to frost. The general appearance, however, very much 

 resembles the action of frost or singeing by fire, inasmuch as the 

 leaves are half withered up, and practical foresters have therefore 

 often associated this appearance with the commencement of " larch 

 disease." It is, however, possible that this insect may play a very 

 important, though indirect, part in connection with the larch disease 



Fig. 268. Normal foliage of 

 larch. 



2(59. Foliage of larch injured by larva; 

 o/Coleophora laricella. 



fungus (Peziza Willkommii). The fungus is most active in spring 

 months, and as the injuries caused by C. laricella on the foliage, 

 together with the obvious effect of checking the rate of growth, have a 

 tendency to reduce the plant below par, it follows that the fungus is 

 materially assisted in its action, and can therefore do greater damage. 

 Fig. 268 represents the normal foliage, and fig. 269 the injured shoots. 

 The small caterpillars which do this damage hatch out in July, and 

 feed on the leaves of young trees from six to thirty years of age, but 

 as a rule they are most destructive to trees of the latter age. At first 



