HEMIPTERA. 191 



that the females of the dog-day harvest-fly prefer to hiy their 

 eggs ill one rather than in another kind of tree; for I liave 

 taken the pupae emerging from the ground beneath cherry, 

 maple, and elm trees, and it is probable that they could not 

 have travelled far from the trees upon which, when young, they 

 were hatched, and upon the trunks of which they finally leave 

 their vacant shells. These have much the same form and 

 appearance as the pupa-shells of the seventeen-year harvest- 

 fly, but are considerably larger. Some individuals of this 

 species continue with us as late as the end of September. As 

 they are not very numerous, the injury sustained by the trees 

 from their punctures is comparatively small. 



The other harvest-flies of this country have only two eyelets, 

 and are not furnished with musical instruments; but they 

 enjoy the faculty of leaping, which the Cicadas do not. This 

 faculty does not, as in the grasshoppers and other leaping 

 insects, result from an enlargement of their hindmost thighs, 

 which do not differ much in thickness from the others; but is 

 owing to the length of their hindmost shanks, or to the bristles 

 and spines with which these parts are clothed and tipped. 

 These spines serve to fix the hind legs securely to the surface, 

 and, when the insect suddenly unbends its legs, its body is 

 launched forward in the air. Some of these harvest-flies, 

 w^hen assisted by their wings, will leap to the distance of five 

 or six feet, which is more than two hundred and fifty times 

 their own length; in the same proportion, "a man of ordinary 

 stature should be able at once to vault through the an* to the 

 distance of a quarter of a mile." Some of these leaping har- 

 vest-flies have the face nearly vertical, and the thorax very large, 

 tapering to a point behind, covering the whole of the upper side 

 of the body, and overtopping even the head, which is not visible 

 from above. These belong chiefly to the genus Membracis, to 

 which allusion has akeady been made ; and, as they are found 

 mostly on the limbs of trees and shrubs, they may receive the 

 name of tree-hoppers.* In others the face slopes downwards 



* Mr. Rennie, in the " Library of Entertaining Knowledge," has misapplied 

 this name to the Cicadas, -which do not leap. 



