VI 
Introduction 
riodicals with minor exceptions, the chief difference being that the names of 
countries, states, cities and other geographical units are not abbreviated. 
A few references are listed under their titles rather than under the ab- 
breviations of the journals in which they were published, because in these 
cases the titles are usually better known than the journals, for example, 
Van Duzee 1917 Catalogue of Hemiptera of American North of Mexico 
not Techn. Bull. California Agr. Exp. Sta. Ent. 2. If the journal has been 
published in series the abbreviation of the journal is followed by a series 
number or by such an abbreviation as n. s. (new series), o. s. (old series), 
n. f. (neue Folge), or the like. This is followed by a note indicating the 
nature of the reference. 
The notes which follow the references are generally self explanatory, 
but three points may be mentioned here. Such notations as “[described],” 
“[notes],” “[key],” and the like are intended to be suggestive rather than 
precise or exclusive. The notation “[error]” means not accepted in this 
catalogue. Usually the latest published synonymy is accepted, but not 
always. The other notation “[comparative note]” is used to designate 
those references, often of the greatest taxonomic significance, in which two 
generic, specific or other groups are compared. All references have been 
checked against the original save those marked with an asterisk (*), which 
have been accepted from reliable sources. Every effort has been made to 
have the references full and complete and to give an indication of the 
character of the data contained. Where the writer knows that reprints 
have been issued with different pagination, this is indicated in parentheses 
following the page numbers of the original. In a few cases, where the matter 
has been reprinted under a different title with different pagination, separate 
references are given. Where authentic editions have been published these 
have been indicated by separate references. Genera established without 
included species have been dated from their original description, with 
their type fixation dated at the time of the first inclusion of species. Original 
spellings have been retained in all cases, except obvious typographical 
errors. Typographical errors are indicated by placing “[sic]” after the mis- 
spelled name. This is not for the purpose of calling attention to the mistakes 
authors have made but to make certain that students following the cata- 
logue have a clear understanding of what is implied. 
The determination of obvious typographical errors is not always easy. 
These errors range all the way from clearly apparent transpositions of 
letters, to misspelled names of individuals, geographical names, and many 
others of like character. However, so many generic names have been 
formed by the transposition and substitution of letters that one is often 
at a loss to know which names are misspelled and which are not. For 
example, Neokolla and Keonolla, or Alebra, Elebra, and Enalebra. 
