6 THE UNIVERSITY SCIENCE BULLETIN. 



It would seem that with five lists already published of the 

 Cicadellid fauna of the state, that some other group might 

 well have been chosen for further work. State lists, such as 

 the ones referred to, are of great value to systematic ento- 

 mologists in determining the geographical distribution and 

 limits of the species enumerated, but to the beginner, who 

 starts out to get acquainted with the fauna of a given region, 

 they cannot be of much help, other than to inform him that 

 he might or ought to run across the species so listed. Accord- 

 ingly we have thought that a systematic treatise of the known 

 Kansas forms might not be out of place. 



It has been our aim to make this paper something more than 

 a state list. The attempt has been made to provide, rather, 

 a sort of manual for the study of our native forms. Accord- 

 ingly keys have been provided for the separation of all the 

 groups down to species, descriptions have been written for all 

 the species known to occur in the state, and, as far as possible, 

 host plant and locality records have been added to assist in 

 the finding of any desired species. 



We have, moreover, attempted to bring together our latest 

 knowledge concerning the economic importance of this family. 

 Many articles have been written on this subject, but each 

 treats only of some particular phase of it. It has been thought 

 that a summing up of our knowledge on this subject might 

 help to a correct appreciation of the economic position of this 

 group. 



The systematic position of this and of related families is 

 of interest to the systematist. We have not tried to advance 

 any essentially new ideas on the subject, but have thought it 

 advisable to give what seem to be the prevailing ideas on 

 this line. 



No attempt has been made to give a detailed description of 

 the morphology of the Cicadellldse. We have included only 

 a brief chapter on this phase, just enough to enable one to 

 properly use the keys and understand the descriptions. But 

 we have gone rather fully into a study of what we have called 

 the "internal male genitalia." This is what may properly be 

 considered the original part of this paper, and therefore we 

 have devoted a whole chapter to its discussion. 



It should be said here that the list of species is by no means 

 complete. We know of some species, previously listed as oc- 

 curring in the state, which are here omitted. This has been 



