THE HOMOPTERA 



187 



these may, for convenience, be combined here. The six to be considered 

 therefore are: 



Order Homoptera 



Cicadas (Cicadidse). 



Leaf Hoppers and Tree Hoppers (four families). 



Jumping Plant Lice (Chermidae). 



Plant Lice (Aphididae). 



White Flies ( Aleyrodidse) . 



Scale Insects (Coccidae). 



Family Cicadidae (The Cicadas) . Most of the members of this family 

 are rather large insects, with bodies often two or three inches or even 

 more in length and quite stout as well. Their wings are correspondingly 

 large, and in some species have a spread of more than six inches. Though 

 usually transparent and with prominent veins they sometimes have 

 pigmented areas of various colors. 



The adults place their eggs in slits they make with their ovipositors 

 in twigs. On hatching the nymphs drop to the ground and make their 

 way to the roots where they feed on the sap. Metamorphosis is more 

 nearly a complete one than in the other families of Homoptera (except 

 the scales) , the nymph having but little resemblance to the adult, and the 

 last two nymphal stages are rather transitional in appearance between the 

 two. 



The adult males have vocal organs located on the under side of the 

 basal segments of the abdomen and covered by extensions backward of 

 the metathorax. The sound produced is often so loud, especially when 

 the insects are abundant, as to be very noticeable and even unpleasant. 

 No auditory organ has as yet been discovered with certainty, in either 

 sex. 



Cicadas are particularly inhabitants of warm countries, though some 

 species are abundant quite far from these regions. In North America 

 they occur in Canada and probably in 

 all the States farther south, and are 

 found as far north as England in the 

 Old World. They are often wrongly 

 called locusts. 



The Periodical Cicada or Seventeen- 

 year Locust (Tibicina septendecim Say). 

 This remarkable insect is a native of 

 North America. It is found from Mass- 

 achusetts to Northern Florida and west 

 to Wisconsin, Iowa, Kansas, Oklahoma 

 and Texas, but is much less important near its northern limits than near 

 the center of its range. 



The adult (Fig. 178) is about an inch long, with a stout, black body, 

 orange eyes, legs and wing veins. The wings when at rest extend consid- 



FIG. 178. Adult Periodical Cicada 

 natural size. 



