114 Hemiptera-Homoptera. 



ful description of the manner in wliich this is done, see 

 Harris 2, 211. 



The larvcc hatch in about six weeks. They volun- 

 tarily drop to the ground, where they bury themselves. 

 The period that they remain here wants only a few 

 weeks of being seventeen years. They derive their 

 nourishment, during this time, from the roots of dif- 

 ferent plants. The larvae are sometimes found at great 

 depth, — five to ten feet. 



Note form of galleries, and the extensions of them 

 above the ground, which the pupae sometimes build. 



They emerge from the ground during the last half 

 of May, at which time the empty pupa-skins may be 

 found, in great numbers, clinging to bark of trees, and 

 to other objects. They pair, the females oviposit, and 

 all disappear in a few weeks. 



The injury done to fruit trees, by the females, when 

 depositing their eggs, is sometimes very great. 



These insects are called locusts only in America. 

 The locusts of other countries belong to the Orthop- 

 tera, and are what we call grasshoppers. Keep this 

 fact in mind when reading European works. (3, I., 



18; 4. I-. 38; 5. I- 63)- 



The thirteen year locust, Cicada trcdcchii Riley, is 

 the name given to a variety of C. scptcndecim which 

 matures in thirteen years. (3, I., 18). 



The Dog-day Harvest-fly, Cicada pruinosa Say. — 

 This is the common species in Ithaca. It is larger 

 than C. scptendccini. The top of the head and thorax 

 is marked with green lines ; and the veins on the basal 

 half of the anterior wings are of the same color. The 

 veins beyond the middle of the wings are brownish. 

 The body beneath is pruinose, hence the specific 

 name. 



