HEMIPTERA. 177 



I am not aware that the females of the dog-day harvest-fly prefer 

 to lay their eggs in one rather than in another kind of tree ; for I 

 have 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 con- 

 siderably larger. Some individuals of this species continue with 

 us as late as the end of September. As they are not very nu- 

 merous, 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 hinder shanks, or to the bristles and spines with which these 

 parts are clothed and tipped. These spines serve to fix the hind- 

 legs s~'ecurely to the surface, and, when the insect suddenly un- 

 bends its legs, its body is launched forward in the air. Some of 

 these harvest-flies, when 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 air 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 already been made ; and, as they are found 

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



believe, was captured in Florida, and was presented to me by Mr. Edward Double- 

 day. A specimen of the tibicen, or some other large species, has been taken in 

 Massachusetts ; but I have not the individual to refer to at this time. 



23 



