﻿BIOLOGICAL SURVEY. 



(a) LIFE HISTORIES OF HOPPERS, 



Compared with the Life Histories of Hymenoptera, Diptera, 

 and certain Coleoptera. for example, t'hose of the leaf-hoppers 

 are, as a rule, of small interest. 



The outward form, at least, is generally, in the^nym])hal in- 

 stars, very similar to that of the adult, the latter differing prin- 

 cipally in maturation of the organs of flight and reproduction, 

 together with an increase in the number of tarsal segments, and 

 modifications, mostly slight, in the form of the head. 



There is also comparatively little scope for multifariousness 

 in the Jiihifs of the leaf-hoppers. Some are abnormal, others 

 live among grasses and lowly herbage ; some in dry pastures, 

 others in reedy margins of lakes and streams. Many are at- 

 tended more or less assiduously by ants, a few are found actually 

 associated with the latter in their nests, though their role there 

 is unknown. Some are solitary, other herd in flocks, among the 

 HKXst curious of the latter being such genera of the Derbinae as 

 I'JiiladcIphcia and Sardis which sit on the undersurface of leaves 

 in ordered rows with their elongate tegmina raised perpencFic- 

 ularly over the back. 



The different superfamilies may be easily recognized apart, in 

 the nymphal instars as in the adult state. The Fulgoroidea are 

 extraordinarily sensorized, the head being almost always fur- 

 nished with many specialized sensory pits, these often occuring 

 also on the nota, tegminal pads and even on the abdomen. I 

 believe that the number and disposition of these organs will 

 prove of great value in future classification. The genae, an- 

 tennae, etc., are much as in the adult. 



In the other superfamilies the pits are apparently entirely ab- 

 sent, though there are sometimes simple, scattered piligerous 

 pits on the abdomen. The Cicadoidea have the anterior femora 

 greatly thickened and spinose. The nymphal Tetigonioidea 

 partake of the general characteristics of the adults, tho in the 

 Membracidae, many nymphal forms are very strongly granulate. 

 These granulations, however, not being pierced or piliferous. 

 (PI. XXIV, figs. IO-I2.) 



