382 W. D. FUNKHOUSER 



four hours. If the msects are injured during this period the injury becomes 

 permanent and the mutilation may appear as a grotesque twist or bend 

 in the hardened pronotum. It is not unlikely that such injured speci- 

 mens have given rise to certain new species and varieties, the descriptions 

 of which have been based on apparently new pronotal characters. 



RELATION OF NYMPHS AND ADULTS TO HOSTS 



After reaching the adult stage the insect often moves to a different 

 host from that on which the eggs were laid. In fact such migration 

 may take place during the last or the next to the last nymphal instar. 

 In some cases a clear distinction between the host used for oviposition 

 and that used as a food plant may be made; in other cases the insect 

 spends its entire life on one plant which serves both as food and as an 

 egg host. In the latter case both nymphs and adults may be taken 

 together, and apparently they lead a more or less gregarious existence. 



BROODS 



Most of the local species have but one brood a year. A few exceptions, 

 however, may be noted. Campylenchia latipes normally has two broods 

 and some of the adults of the second brood winter over in that stage. 

 Ceresa horealis has two broods, but the adults of the second brood die 

 after depositing their eggs. Stictocephala inermis is believed to have two 

 broods, at least in certain years when the seasons are favorable. Wilder- 

 muth (1915:357) reports four generations for the closely related species 

 S. festina in Arizona, where no hibernation is required. Cyrtolohus vau 

 has two broods, and in some seasons three if warm weather continues late 

 in the fall. It may be that in some instances the adults of the last brood 

 of this species may survive the winter, Vanduzea arquata may have 

 four broods during the year, three from the summer and one from the 

 winter eggs. This is the largest number of generations in a year for 

 any of the species studied. Entylia hactriana has two, and possibly 

 three, broods a year. Miss Branch (1913:84) estimates six or seven 

 broods a year for the closely related species Entylia sinuata in Kansas. 



The number of broods in a year is, however, very largely dependent 

 on the weather conditions of the seasons concerned. It is very probable 

 that a decided variation in number of broods may occur in different 

 parts of the country, and that the data reported for the Cayuga Lake 



