Introduction 
v 
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 suggestions 
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 of this system. We are confronted by so many coined words 
that can have no sex that it seems better to use this system and disregard 
apparent violations of Latin and Greek grammar. Where the sex 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 elimi¬ 
nate 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 when pub¬ 
lished in the proceedings of local natural history societies, references to 
species of economic importance when published in scientific agricultural 
journals, references to vectors of plant diseases when published in phyto- 
pathological journals, and many other 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 changes in 
the nomenclature adopted in this catalogue should not 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 Cercopidae is the second part of 
the Cercopoidea. 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, N. C. State College, who worked 
with Dr. Metcalf for seven years, and the technical advice of Dr. David 
A. Young, N. C. State College, and Dr. W. H. Anderson, Insect Identifi¬ 
cation and Parasite Introduction Laboratories, U. S. Department of 
Agriculture, Beltsville, Maryland. 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 publica¬ 
tion costs. It is believed that the revised method of literature citation will 
cause no great inconvenience to the reader. Dr. Metcalf himself advocated 
it under certain conditions in the past, and it is felt that the use of abbrevi¬ 
ated literature citations in his catalogues would have met with his approval. 
