WALKING-STICKS AND WALKING-LEAVES. 45 



lying close to leaves and the branches of low shrubs, 

 and are strictly herbivorous. They devour the leaves, 

 and especially the young glutinous or gummy shoots of 

 the plants on which they reside, and with a voracity so 

 excessive that a single pair will destroy a great quantity 

 of foliage, so that in some parts of the world where they 

 abound they become very injurious. This occurs in the 

 South Sea Isles, in the case of Graeffea coccophagus, a 

 brown slender species, which sometimes commits dreadful 

 devastation in the plantations of cocoanut trees, occa- 

 sioning scarcity of food, and orders have been issued 

 by the chiefs for their destruction. One writer goes so 

 far as to ascribe the cannibalism in some of these islands 

 to the want of food caused by the ravages of this insect. 

 Diapheromera femorata, common over the greater part 

 of the United States, has also on several occasions 

 appeared in such numbers as to be seriously destructive 

 to foliage in the forests. But taken as a whole, they 

 are far from abundant enough to do any real harm. 



Immobility; the Reason and the Use thereof. 



Their large size notwithstanding, they are timid 

 inoffensive creatures, and of sluggish mode of life, as 

 their structure indicates-. Their body is much too 

 linear, and too long, in the majority of species, to be 



