Nearly two thousand of my Coleoptera, and many hundreds of my
butterflies, have been already described by various eminent
naturalists, British and foreign; but a much larger number
remains undescribed. Among those to whom science is most indebted
for this laborious work, I must name Mr. F. P. Pascoe, late
President of the Entomological Society of London, who had almost
completed the classification and description of my large
collection of Longicorn beetles (now in his possession),
comprising more than a thousand species, of which at least nine
hundred were previously undescribed and new to European cabinets.

The remaining orders of insects, comprising probably more than
two thousand species, are in the collection of Mr. William Wilson
Saunders, who has caused the larger portion of them to be
described by good entomologists. The Hymenoptera alone amounted
to more than nine hundred species, among which were two hundred
and eighty different kinds of ants, of which two hundred were
new.

The six years' delay in publishing my travels thus enables me to
give what I hope may be an interesting and instructive sketch of
the main results yet arrived at by the study of my collections;
and as the countries I have to describe are not much visited or
written about, and their social and physical conditions are not
liable to rapid change, I believe and hope that my readers will
gain much more than they will lose by not having read my book six
years ago, and by this time perhaps forgotten all about it.

I must now say a few words on the plan of my work.