410 W. D. FUNKHOUSER 



not congregate as individuals nor mingle with other Memhracidae. Such 

 species are illustrated by Campylenchia curvata, Archasia Belfragei, Smilia 

 camelus, and Ophiderma puhescens. This is not to be explained by the 

 host plant or by the attendance or non-attendance of ants. Archasia 

 Belfragei and Smilia camelus, for example, live on the locust, on which 

 host Vanduzea arquata and Thelia himaculata congregate in large numbers. 

 It may be noted in the same connection that a greater number of species 

 of Membracidae are found on the oak thaii on any other local host plant, 

 and yet none of the species on this tree are given to communal life. 



The species of the genus usually agree in showing a communal or a 

 solitary life. A number of the species of certain genera are so rare locally, 

 however, that this point has not been satisfactorily established. 



In general the species of the basin seem to fall into five groups, as 

 follows : 



1. Species living with other species— Thelia himaculata and Vanduzea 

 arquata. 



2. Species living together as individuals but not living with other species 

 — Entylia bactriana. 



3. Species living together as nymphs but not as adults — Ceresa bubalus. 



4. Species living together as adults ])ut not as nymphs — Carynota mera. 



5. Species entirely solitary as both nymphs and adults — Smilia camelus. 



ECOLOGY 



Environmental conditions undoubtedly play an important part in the 

 life history of the various species of Membracidae, and it seems very 

 likely that when a sufficient amount of experimental data is available 

 it will be found that many of the seeming irregularities in the periods 

 of development which have been noted for the local forms may be explained 

 by the variation in temperature and moisture to which the eggs and the 

 nymphs are subjected. The experiments and observations made in the 

 course of this study seem to show that seasonal variations in weather 

 conditions, extremes of temperature for both long and short periods, 

 moisture and humidity for the basin and for definite localities, and the 

 physiological condition of the hosts used for oviposition and feeding, 

 all have noticeable effects on the life of the species of this family. Detailed 

 reports of the separate experiments and field records would be more or 

 less alike and would necessitate unnecessary repetition, but type illus- 

 trations may be used which it is believed are representative of the main 

 factors in ecology as noted. 



