GREEN GRASSHOPPERS (LOCUSTID&). 145 



it is a matter of wonder how the Microcentrum could so 

 recently have been compressed into the comparatively 

 small shell beside it. After a few minutes the little 

 beings essay their first leaps, and soon commence to eat 

 with avidity. 



Including the moult in leaving the egg, they cast 

 skins five times, acquiring wings at the fifth. Almost 

 the first efforts of the liberated insect are directed to 

 the task of eating up its out-grown and out-worn integu- 

 ment. Post-embryonic development takes about ten 

 weeks. When first out of the pupal covering, the wings 

 hang down on each side, limp and shapeless, but soon 

 begin to dry and harden, and gradually are drawn into 

 place, and assume their green colour. 



Ears. 



The Locustidse resemble the Acridiidse in the pos- 

 session of special organs of hearing, or ears, but their 

 situation is not the same as in Acridiidae. In Locustidae, 

 in both sexes, a pair of ears usually occur near the 

 proximal end of each tibia of the front pair of legs ; 

 a tympanum, or a slit or crack opening into a cavity in 

 which the tympanum is placed, is seen on each side of 

 the legs. The ears may be divided into two principal 

 kinds, according to the state of the tympanum, which 

 is either exposed, or hid by a prominence of the 



