338 ZOOLOGY 
with a large vertical head. The antennae are short, and the 
hind legs are enlarged for jumping ; the tarsus has three joints ; 
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Fic. 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 
