TRUE ORTHOPTERA 3147 



chiefly on the grasses of different kinds, including most of the cultivated grains; 

 but locusts leave scarcely anything in the nature of vegetation untouched, when, as 

 often happens, they invade a district where the ordinary herbs and grasses are in- 

 sufficient to support their vast numbers. Trees and shrubs are then stripped bare 

 of their leaves, and the bark and wood even are not spared. Pressed by hunger, 

 locusts do not refrain from attacking plants which at ordinary times they seem to 

 avoid. They frequently devour their own dead, and even carry their cannibalism so 

 far as to kill and eat the newly-molted and soft-skinned larvae. Different species 

 of these destructive insects are found in all the great regions of the world; though 

 North Africa is, perhaps, the one which suffers most from their ravages. The 

 locusts referred to in Scripture belonged in all probability for the most part to the 

 species known as Schistocerca peregrina, which has its chief home in the Sahara and 

 surrounding districts. 



Several other species are found in North Africa, and in South Africa Pachy- 

 fylus migratorioides is one of the most widely distributed. Great swarms of 

 locusts of this species have been seen at different times in recent years; one which 

 passed over Pretoria in 1891 was estimated to be twenty-five miles long, one and 

 a half broad, and half a mile in depth. It was probably to this species also those 

 locusts belonged, of which Barrow, giving an account of their ravages in the year 

 1797, states that the whole surface of the ground over an area of about two thou- 

 sand square miles was literally covered with them; and that when driven into the 

 sea by a northwest wind, they formed a bank on the shore three or four feet high 

 and fifty miles long. Among European locusts, the best known is P. migratorius, 

 which occurs chiefly in the southeast, and is found also in Egypt and in West and 

 Central Asia. 



Passing from the locusts, we may briefly notice a few of the other insects of 

 the family. The Tryxalincz are remarkable on account of the peculiar shape of 

 their head, to which we have already 

 alluded. No species of this sub- 

 family is found in Britain. In the 

 allied Tettigincz the pronotum is 

 produced behind into a long process, 

 which in some of the species reaches 

 beyond the tip of the abdomen. Two 

 of the smallest species of grass- 

 hoppers found in Great Britain be- 

 long to the genus Tettix the typical 

 genus of this subfamily. The genus 

 Pneumora, which is represented only 

 in South Africa, is characterized by Tettix subulata. 



the bladder-like dilatation of the ab- (Natural size.) 



domen in one of the sexes. The 

 hind-legs in this genus are rather short, and are scarcely adapted for leaping. 



The stick and leaf insects (Phasmatidce} are chiefly interesting on account of 

 their resemblance to the objects after which they are named. They form one of the 



