INTRODUCTION V 



by Arabic letters, Greek letters, numbers, or other designations. All 

 varieties are catalogued, however, under the first designation regard- 

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

 species with further study and then may be given latinized 

 designations. 



Primary homonyms of species have been replaced by nonuQia nova; 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 sug- 

 gestions 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 limita- 

 tions are outweighed by the advantages. We are confronted by so 

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

 this system and disregard apparent violations of Latin and Greek 

 grammar. Where the gender of generic names can be determined, 

 the appropriate adjustments are made in the specific names. 



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

 eliminate all errors. We will 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 societies, 

 references to species of economic importance published in scientific 

 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 Ulopidae is the fifth 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 tech- 

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

 and Dr. P. W. Oman, formerly in charge of the Insect Identification 

 and Parasite Introduction Research Branch, Entomology Research 

 Division, Agricultural Research Service, U.S. Department of Agri- 

 culture, Beltsville, Md. The higher categories utilized in this classi- 

 fication 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 



