PLANT-EATING INSECTS AND MYRIAPODS 213 



ledge, to use the well-understood terms of human physiology in 

 a broad and general sense. These animals, however, are not 

 vegetarians pure and simple, for they eat their own cast skins 

 and the bodies of deceased friends. Cannibalism is also prac- 

 tised, especially by the " soldiers " — specialized blind individuals 

 with large heads and huge mandibles incapable of dealing with 

 the staple food. 



A curious Natal species of Termite, described by Haviland, 

 cuts grass and acacia leaves into pieces which are carried into 

 the nest, and it would appear likely that this is for the purpose 

 of fungus cultivation, as in some true Ants (see p. 209), for the 

 same observer has shown that there are both South African and 

 Singapore species which engage in this kind of culture. Such 

 habits of complex insect -communities are curiously reminiscent 

 of the agricultural stage in the history of prehistoric man, which 

 marks the most important step in the evolution of civilized races. 



STRAIGHT-WINGED INSECTS (Orthoptera) 



The insects of this large and comparatively primitive order 

 possess biting mouth-parts, already (vol. i, p. 345) described in 

 detail in the case of the Common Cockroach. Most of the 

 species are either entirely vegetarian, or at any rate plant food 

 bulks largely in their diet. Among the most notable plant-eating 

 members of the order are the Grasshoppers and Locusts 

 {Acridiidcs), distinguished by their comparatively short feelers. 

 A "locust", as defined by Sharp (in The Cambridge Natural 

 History), is simply "a species of grasshopper that occasionally 

 increases greatly in numbers, and that moves about in swarms 

 to seek fresh food ". A great deal of damage is done by such 

 insects both in Old and New Worlds. To most readers the 

 word "locust" chiefly suggests the creature so called in Exodus, 

 and there described as one of the Egyptian plagues (Exodus, 

 X. 4-6). The Migratory Locust of North Africa and North- 

 west India, Schistocerca [Acridium) peregrina, is most likely the 

 species meant (see vol. i, p. 382). 



WINGLESS INSECTS (Aptera) 



This order includes small wingless forms which are usually 

 regarded as primitive (see vol. i, p. 384). Their mouth-parts 

 are feeble, and may approach to the suctorial type. Very little 



