LEAF-BEETLES. 



149 



for this purpose, are in the market. But it should be recollected 

 that the spraying should be done as soon as the beetles begin feed- 

 ing in spring, so as to kill the adults before they have deposited 

 their eggs. Our people usually wait until the damage caused by 

 all kinds of insects becomes plainly visible, which is not a wise 

 thing to do, as in such a case the application of the arsenites will 

 simply check the trouble ; the proper way to do is to nip the 

 evil in the bud, and to do so an early warfare is absolutely neces- 

 sary. 



The very similar genus Lina also contains numerous very 

 destructive beetles, which, however, devote all their attention to 

 devouring the foliage of willows and poplars, in which they suc- 

 ceed only too well, as may be seen in some wind-breaks, which 

 are defoliated year after year by these and some other insects, 

 and to such an extent that they are as bare of green leaves in sum- 

 mer as during the winter. A timely application of arsenites 

 would prevent this injury, which, repeated year after year, can 

 result in but one way, the death of the infested plants. It seems 

 as if many persons did not know the old proverb "an ounce of 

 prevention is worth a pound of cure." 



One species of Lina (L. tremulae Fab.), exceedingly abun- 

 dant and injurious in the north, is illustrated in Fig. 152, and 

 a still more destructive kind, the L. scripta Fab., in Fig. 153. It 

 sometimes devours all the leaves of willows in our wind breaks. 



'S if if 



b \ c V J 



Fig. 153. — Varieties of Lina scripta, Fab. — After Division of Entomology, U. S. 

 Department of Agriculture. 



There is another small group of leaf-feeding beetles called 

 the Diabroticcis. They are rather slender and soft, with long 

 feelers ; their color is green or yellow, with black spots or lines. 

 Prof. Smith, in his book already mentioned, gives the following 

 account of them : 



