Biology of the Membracidae of the Cayuga Lake Basin 421 



may be presumed to be far from tempting as a morsel of food. Moreover 

 the sharp, hard spines which in many species project in many directions 

 may deter the captor from swallowing the membracid even if captured. 

 It should be remembered that l^esides the frontal horns possessed bj^ many 

 membracids, and the rough humeral angles possessed l)y most, the posterior 

 process usually projects in a very sharp spine and is in some cases capable 

 of inflicting a wound of no mean proportions. 



Thus the shape, color, habits, ability to hide, power of flight, and 

 skeletal armor are all to be included in the list of methods of protection — 

 a list sufficiently long and varied to give satisfactory results. 



ECONOMIC IMPORTANCE 



As a family, the Membracidae are not to he considered as of great 

 economic importance in the Cayuga Lake Basin. Even the three or four 

 species that have been credited with destructiveness in other parts of the 

 country and that are here represented are of no particular importance 

 locally so far as damage to host plants is concerned. 



The manner in which membracids have been known to cause damage 

 is limited to two habits, feeding and oviposition. Of these the latter 

 is the more harmful. 



So far as feeding is concerned there is Uttle evidence that Membracidae 

 cause any injuiy to the host, either locally or otherwise. The quantity 

 of sap consumed by the insects is negligible, and the wounds made by the 

 incisions of their beaks are neither large enovigh to destroy tissue nor 

 extensive enough to offer opportunity for infection. In fact such incisions 

 cannot usually be found even with a microscope a few hours after the 

 process. Trees that are literally covered with Membracidae seem in no 

 way less healthy than those on which no insects are present. Careful 

 examination of trees in the field show aljsolutely no indication of injuiy 

 from feeding habits. 



The egg-laying process may be more destructive, but even this process 

 is of no local concern. In most cases the slit made by the ovipositor 

 is clean and sharp and very superficial, seldom extending to the cambium 

 and usually healing at once without a scar. The phloem tissue if injured 

 is not so extensively damaged as to interfere with its function, and the 

 injured part, in dicotyledons at least, would usually slough off naturally 

 within the first or the second season. The ovipositor in most of the 



