40 INTRODUCTION TO ZOOLOGY. 



6. If your specimen is a male, note the air sac in 

 each side of the dorsal surface of the abdomen. See 

 the thin plates on the ventral side of the abdomen, 

 which are used in producing the sound. 



7. If your specimen is a female, study the oviposi- 

 tor carefully. 



8. Draw the entire insect. 



Additional Facts About the Cicada. 



Either the seventeen year Cicada, or the common 

 harvest fly, may be used in making this study. There 

 are very few insects that live longer than the sev- 

 enteen year cicada. It lives under the ground as 

 a larva or pupa for seventeen years, then suddenly 

 makes its appearance in May or June, transforms to 

 the imago stage, lives for three or four weeks, lays its 

 eggs, and dies. The eggs are laid in a groove cut by 

 the female in the young twigs of trees. The eggs 

 hatch and the larvsedrop to the ground, in which they 

 disappear and are seen no more for seventeen years. 

 The twigs in which the eggs are laid frequently die 

 from the injury received, and as a result much dam- 

 age is done, especially to fruit trees. There are in this 

 country about twenty-three broods of the seventeen 

 year locusts, so that at least one brood is likely to 

 appear somewhere in the United States every year. 

 There is also a thirteen-year form, of which several 

 small broods exist in the United States. The common 

 harvest fly, or dry fly. Cicada pruinosa, lives only 

 two years. 



The Cicadas are noticeable for the very loud noise 

 they make. Under ordinary conditions, the song of 

 a single Cicada can be heard for at least a mile. 



The Cicada and the giant water bug represent two 

 divisions of the order Hemiptera. All the insects of 

 this order have the sucking mouth parts and incom- 



