PREFACE. 
The ‘ Trogonidse ’ was the second Monograph undertaken by me, and was published in 
1838. I quote the following phrases from my preface to the original edition, as it shows 
our position in regard to this family of birds nearly forty years ago, after the most 
strenuous exertions to arrive at a complete knowledge of them :— 
“Having brought this Monograph to a close, I am led to hope that my labours in 
the elucidation of a tribe of birds hitherto involved in much confusion will not be 
destitute of some degree of value, more especially in the eyes of ornithologists, introducing 
to their notice, as it does, many new species, and clearing up the difficulties with which 
many of those even common in our cabinets have been previously surrounded,—difficulties 
arising from several causes, among which may be enumerated the differences in plumage 
which obtain so often between the males and females, as well as between the young 
males and the adults of the same sex, in some of the minor groups; to which may 
lie added the circumstance of the subject not having been attempted by naturalists 
possessing command of those ample resources necessary for extricating the subject from 
the labyrinth of confusion in which it has long been involved. 
“ It would be presumptuous in me to say that this Monograph is fully completed, or 
that I have figured every existing species; on the contrary, I have reason to believe 
that many will yet be discovered, both in the Old and New World, particularly in 
those remote regions which civilized man has seldom, if ever, visited: but in order to 
render the work complete up to the present time, I have not only done my utmost to 
add every species to my own collection, hut have visited all the principal Museums of 
Europe, both public and private, and, as in previous instances, have experienced the 
greatest kindness and cooperation from the various eminent naturalists, private indivi¬ 
duals, and the officers of the natural-history department of every public institution. 
Indeed, without the liberality I have experienced, it would be impossible that a work 
