Insect Damage 47 



destroy the entire leaf. But the larvce of beetles also, and 

 some of the beetles themselves are destructive in this 

 manner. 



The leaf-miners, which skeletonize leaves, eating only 

 the softer portions in patches, also come from different fam- 

 ilies. Some of these, hke the elm-leaf beetle and the larch- 

 miner, make such extensive inroads, that the result is very 

 much Hke the eating of the whole leaf. Others make only 

 small, blotch-like mines or short tracks on upper or lower, 

 or both sides of the leaves, destroying small areas of the 

 soft tissues. These, as a rule, do little damage. Neverthe- 

 less it is wise to reduce them by burning up the fallen leaves, 

 in which they usually hibernate. 



Another set, the leaf-rollers, also coming from different 

 families, roll the leaves together in various ways to make 

 shelter for the caterpillars, folding the edges and sewing 

 them together with silken threads, or spinning them, as in 

 the case of needles of conifers, into a web. These distor- 

 tions and occultations of the foliage would generally be of 

 little consequence, but the insect, here sheltered, usually 

 is destructive to the buds and }oung shoots, and, if the 

 leaves in the web are eaten, as is done by some, the damage 

 may become considerable. 



While the leaf insects so far mentioned feed on the foliage 

 by eating it, there are a few, like the plant-hce and leaf- 

 hoppers, w^hich suck the sap by piercing the succulent leaves 

 and leaf stems or even twigs, causing the leaves to crumple 

 or roll, or producing gall-like sw^ellings. Usually these 

 leaf-suckers do not do much damage unless unusually abun- 

 dant. There are, however, some bark-lice which do much 

 more damage by puncturing the bark of twigs. 



To this group belong also various scale-insects, which, 

 adhering to the small limbs, sap their life and cause them 



