Introduction 
vii 
homonym 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 ad- 
vantages 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 ap- 
parent 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 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 when published 
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 phytopathological 
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. 
Z. P. Metcalf 
and 
Clyde F. Smith 
Raleigh, North Carolina 
April 1956 
