Introduction v 



less of its form. Some of these varieties may prove to be valid species 

 on further study, and then may be given latinized designations. 



Primary homonyms of species have been replaced by nomina nova; 

 secondary homonyms have been restored to their original names if 

 the homonymy has been relieved by moving one or the other, or 

 both species, to other genera. 



All specific endings have been modified to agree with the sugges- 

 tions made by Blackwelder 1940, Journal of the Washington Academy 

 of Sciences 31: 135-140. There are certain disadvantages inherent 

 in this method, but it seems to the writer that these limitations are 

 outweighed by the advantages. We are confronted by so many 

 coined words that can have no gender it seems better to use this 

 sj^stem and disregard apparent violations of Latin and Greek grammar. 

 Where the gender of generic names can be determined, the appro- 

 priate adjustments are made in the specific names. 



In a detailed catalogue such as this it is practically impossible to 

 eliminate all errors. We wUl appreciate it very much if our attention 

 is directed to all such mistakes. It is especially easy to overlook 

 local lists published in the proceedings of local natural history socie- 

 ties, references to species of economic importance published in scien- 

 tific agricultural journals, references to vectors of plant diseases 

 published in phytopathological journals, and references of a similar 

 nature. It will be very much appreciated if authors will send us 

 reprints of all articles dealing with the Homoptera. Also, it would 

 seem that no changes in the nomenclature adopted in this catalogue 

 should be made in the future without a full explanation. 



All literature available to the writer before December 31, 1955, 

 has been included in this catalogue. 



The present catalogue of the Family Ledridae is the fourth part 

 of the Cicadelloidea. This was virtually complete at the time of 

 the death of Dr. Z. P. Metcalf on January 5, 1956. It was completed 

 with the aid of Miss Virginia Wade, research analyst. North Carolina 

 State College, who worked with Dr. Metcalf for 7 years, and the 

 technical advice of Dr. David A. Young, Jr., North Carolina State 

 College, and Dr. P. W. Oman, Insect Identification and Parasite 

 Introduction Research Branch, Entomology Research Division, U.S. 

 Department of Agriculture, Beltsville, Md. The higher categories 

 utilized in this classification are those decided upon by Dr. Metcalf 

 during his work on the catalogue. 



In this part of the catalogue a method of literature citation has 

 been adopted which differs from that used in the catalogues of the 

 fulgoroid families. This change has been instituted to save time, 

 space, and publication costs. It is believed that the revised method 



