6 
Introduction 
are listed under their titles rather than under the abbreviations of the jour- 
nals in which they were published, because in these cases the titles are usu- 
ally better known than the journals, for example, Van Duzee 1917 Catalogue 
of Hemiptera of America 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 cata- 
logue. Usually the latest published synonymy is accepted, but not always. 
The other notation “[comparative note]” is used to designate those refer- 
ences, 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 refer- 
ences 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 parenthesis 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 indi- 
cated 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. Typographi- 
cal errors are indicated by placing “[sic]” after the misspelled name. All 
typographical errors, save those which refer to endings only, are appropri- 
ately cross-referred. The species have also been listed under every known 
combination so that it is possible to find any species without recourse to 
the index, which will be published at the completion of the Fascicle, to- 
gether with the full bibliography. In the meantime persons interested in full 
bibliography may consult the author’s Bibliography of the Homoptera 
(1945). 
A catalogue is not a revision of a group, and the location of the genera 
and species in the present catalogue is merely an attempt to reflect what is 
believed to be the general consensus of the best authorities at the present 
time. Doubtful genera and species have been included to call them to the 
attention of subsequent revisers. 
An attempt has been made throughout this catalogue to interpret all 
references in the light of the period in which they were published. This is 
