60 INSECTS. 



the nymph comes above ground, crawls a little way up a 

 convenient reed or board, fastens its feet firmly, and is 

 ready to transform. The skin splits down the back of 

 both head and thorax ; the perfect insect steps out, rests 

 awhile, and expands and dries its wings, and then flies 

 away with a noisy "whirr" to its new home in the tree 

 tops. 



Study of a Live Specimen. Get an adult specimen for 

 study, and observe : 



1. The shape of its body as a whole. 



2. The point where the rostrum arises from the head. 



3. The position of the eyes and ocelli. 



4. The absence of any neck, and the consequent ap- 

 proximation of cheeks and coxae of the anterior pair of 

 legs. 



5. The markings on the top of the thorax. 



6. The sloping position of the wings. 



7. The structure of the fore wings, that they are not 

 half horny and half membranous, but wholly membranous. 



8. The musical organs at the base of the abdomen 

 above (found only in the males), two ribbed and plaited 

 parchment bags situated in depressions, one on either side 

 of the median dorsal line, provided with powerful muscles 

 for driving air against the fluted surfaces. This sets up 

 vibrations, producing sounds, which vary in different indi- 

 viduals with the proximity and form of the spaces and 

 ribs. 



If the large rostrum of the cicada be dissected, the two 

 pairs of punctorial bristles will be easily found within the 

 sheath. 



Compare adults of cicada and squash bug with refer- 

 ence to shape of head ; place of origin of rostrum ; length 

 of neck ; structure, position, and method of folding, of 

 wings. 



