338 



ZOOLOGY 



with a large vertical head. The antennae are short, and the 

 hind leigs are enlarged for jumping ; the tarsus has three joints ; 



Fig. 189.— Pachytylus migratorius. Natural size. 



they produce a chirping noise by rubbing their tibia against a 

 vein on the anterior wing, and their auditory organ is situated 

 on the first abdominal segment. The female has no projecting 

 ovipositor. The eggs are laid in cocoons in packets of 50 to 

 100 at a time. 



Some of the grasshoppers are very voracious, and as they 

 move in immense swarms, they occasion very considerable 



