LAWSON: KANSAS CICADELLID^. 25 



the habits of any group, for even within the genus we do not 

 find uniformity as to the condition in which hibernation occurs. 

 Thus Empoasca mail overwinters as an adult, while E. unicolor 

 hibernates in the eg^ stage. The nearest that we dare come to 

 generalizing may be to state that the majority of species which 

 oviposit in grass, pass through the winter in the Qgg stage, 

 while a large number of those ovipositing in trees hibernate as 

 adults. It seems, therefore, that the greater number of our 

 forms overwinter in the egg stage. 



The hibernating adults are often found under leaves and 

 rubbish in the woods. This is especially true of many Typhlo- 

 cyhini. Of course where the winters are warm, we can hardly 

 designate any stage as the hibernating stage, for under favor- 

 able circumstances they may breed throughout the year. 



The number of generations per season is also an interesting 

 question. Should we generalize we would say that the ma- 

 jority of species have two generations in a season. As to the 

 rest, some undoubtedly have three or more generations, while 

 some have only one. Thus Gibson claims three generations a 

 year for the clover-leaf hopper in southern Missouri and four 

 or more further south. Professor Osborn says there are two 

 generations a year of Drxculacephala mollipes in Ohio, while 

 Gibson claims six for southern Arizona. Others, like Em- 

 poasca unicolor, have but a single generation. Most members 

 of the genus Deltocephalus have two broods, as do such forms 

 as many members of the genus Euscelis and many of the Ti/- 

 phlocybini. 



