THEIR RELATION TO PLANTS 



53 



sources of weakness, apt to result in a break at any 

 time. I would never advise planting a nursery tree 

 whose trunk had been used by Cicadas for ovipositing. 

 In the Heteropterous series the species are usually 

 larger; but the life histories are simpler and the injury 

 is not materiallv different. Here, among the plant 



Fig. i6. — a, Ccresa bubalas, a tree-hopper, ovipositing in slits b\ the eggs, d, 

 arranged as at c; old scarred punctures at e. 



bugs, the poisoning effect already referred to is often 

 noticeable, and is frequently of more importance than 

 the exhaustion caused by the direct feeding. The 

 chinch-bug may serve as the best known example of 

 the destruction causable by these species and of the 

 results that come only from the enormous numbers 

 in which they feed. There is nothing here but a direct 

 loss of vitality due to the abstraction of the plant juices. 



