Ix 
has been made known, and a rough, preliminary revision made of Westwood’s 
and of Walker’s vaguely defined species, so that a new Catalogue is impera- 
tively necessary. 
Lethierry and Severin’s work has been indispensible to Hemipterists, 
but the absence of a specific index and the usual absence of the name of 
the genus under which a species was described, if different from that accepted 
by the authors, were very inconvenient. I have tried to remedy these defects 
as far as possible. 
In this and the following volumes, every new specific description is 
cited; all, or nearly all, descriptions accompanied by figures; and the best 
of the others; but I have not cited each fresh binomial combination. A 
number of the older references, not coming under the above - mentioned 
heads, has been omitted; they relate mostly to the european fauna and are 
recorded in Reuter’s “Revisio synonymica Heteropterorum palaearcticorum 
quae descripserunt auctores vetustiores (Linnaeus 1758 — Latreille 1806)” 4). 
“Fossil”’ species are included as nearly as possible in their proper 
places. Considerable misapprehension regarding these is due to the absurd 
and unphilosophical separation, by most geologists, of present (Pleistocene) 
time from the rest of the Tertiary (or Kainozoic), as a “Quaternary” Epoch. 
The feeling that the species of the other Tertiary periods are the direct 
precursors, with but little separation in (geologic) time, of present-day forms, 
is thus lost, and these interesting relics are regarded with indifference by 
the majority of entomologists. 
I have prepared small tables of geographical distribution, but although 
perhaps useful as affording a bird’s eye view of this part of the subject, 
they are somewhat unsatisfactory. The number in each column, under the 
subregions or divisions, relates to the number of species (of that genus) 
present in each such division, and does not necessarily accord with the total 
at the end of each line”). 
There have also been cited references to papers on the biology and 
anatomy of the Hemiptera, with lists of food-plants, parasites and predators. 
I fear these are rather meagre, but they have been very insufficiently treated 
in the “Zoological Record’ and kindred works, and are often scattered 
throughout the publications of local societies. The names of plants are 
usually left as recorded originally, as I have no access to complete works 
of local botanical synonymy. 
Every entry has been checked, in the first proof, from the original 
work, except in the few instances where I do not possess this, and I there- 
fore hope that though printer and author are nearly ten thousand miles 
apart, the errors of citation may not be found numerously. 
1) 1888 Act. Soc. Sei. Fennica. XV. 241—315; and 443—812; I have cited it 
very rarely in the Catalogue, as I possess only a separately paged copy (1—458). It 
must however be referred to in all debatable points connected with the older euro- 
pean forms. 
2) T have in preparation a paper on “The geographical distribution of the 
Hemiptera”, which deals somewhat fully with this subject. 
