1 68 Bugs, Cicadas, Aphids, and Scale-insects 



they cut with the sharp ovipositor in the twigs of various trees, in this way 

 often doing much damage to orchards and nurseries. The young hatch 

 in about six weeks and drop to the ground, where they burrow down through 

 cracks and begin their long underground life. They feed on the humus 

 in the soil and, to some extent, on juices sucked from the tree-roots. They 

 grow slowly, moulting probably four or six times at intervals of from 

 two years to four years. In spring or early summer of the seventeenth 

 year (thirteenth in a race in the southern states) they come above ground, 

 and, after hiding for a while under stones and sticks, crawl up on the trunks 

 of trees and there moult for the last time, the winged adult emerging and 

 soon flying into the tree-tops. The various broods or swarms in this country, 

 about twenty in number, are known, and the territory occupied by each 

 has been mapped, so that it is possible for entomologists to predict the 

 appearance of a swarm of seventeen-year cicadas in a particular locality 

 at a particular time. As all the members of one of these swarms issue in 

 the same season, and indeed in the same month or fortnight, they usually 

 attract much attention. The broods to issue in the next few years are the 

 following: a large one in 1905 in the northern half of Illinois, eastern part 

 of Iowa, southern part of Wisconsin, southern edge of Michigan, and northern 

 and western edge of Indiana; a scattered one in 1906 ranging, not contin- 

 uously, from Massachusetts south and west through Long Island, New 

 Jersey, Pennsylvania, Maryland, West Virginia, Ohio, Indiana, Kentucky, 

 Tennessee, North and South Carolina, and northerr Georgia; and a large 

 one in 1907, ranging from central Illinois south and east to the Gulf and 

 Atlantic. 



A considerable number of small insects, often seed-like in shape, or 

 with the thorax prolonged into odd horns, spines, or crests, are included 

 in the families of tree-hoppers (Membracidae) and lantern-flies (Fulgoridae) 



(Fig. 237). Striking members, large and bright- 

 colored, of this latter family are found in the 

 South American tropics, but the North American 

 species are small, and are rarely seen or collected 



p IG 2 , A fulgorid, Siobera by amateurs. Among the commonest of our forms 



tricarinaia. (After Forbes; are the candle-heads, species of Scolops, small 

 insects living on grass and herbage, with the head 



bearing a long slender upcurving projection. The tree-hoppers (Mem- 

 bracidae) almost all suggest small angular brownish seeds or thorns in shape 

 and color. The prothorax is sometimes widely expanded, sometimes 

 lengthened so as to cover nearly the whole body, sometimes humped or 

 crested, sometimes spined or pitted. The unusual form is probably pro- 

 tective, making the insects simulate seeds or other plant structures. The 

 species of Enchenopa (Fig. 239) are curiously horned. E. binotala is common 



