VIII 
PREFACE. 
caused by this way of explaining the illustrations will be compensated by the much greater handiness of the 
work produced thereby. 
A work that comprises such an immense material must naturally abstain as much as possible from 
every possible alteration: that is the duty of the critical monograph. Thus the 9th volume considers its chief 
task lies not in disagreeing on every occasion with older literature, but in appreciating the admirable works 
of former specialists, which are the foundations of this work. 
The present 9th volume completes the second major division of the entire work, inasmuch as all the 
butterflies known on the earth have been dealt with. On 549 plates more than 20 000 figures of butterflies have 
been reproduced, and as the whole text enumerates about 30 000 denominated forms of the butterflies of the 
entire fauna, there is on an average one figure to every second form, so that at least those species which are 
in the possession of the private collector are nearly all represented. 
Beside the numbers of Rhopalocerci, 400 plates of Heterocera have been produced, so that, when the 
exotic Saturnidcie and Sphingidae have been completely written up, all the larger moths will have been classified 
except the few genera of the Cossidae and Noctuidae — so the final manufacture of all the material is soon 
to be expected. In any case, a considerable part of the pause of nearly ten years, caused by war and revolution, 
and during which the work made but slow progress, can be made up. The noticeable recovery and strengthening 
brought about by my recent stay in Central Brazil will, I trust, make itself apparent, after my return to Europe, 
in the speedy completion of the work. 
For the present, I beg to expi'ess my sincere thanks to all who have aided me in the accomplishment 
of my great task: particularly to Prof. Dr. Drattdt of Darmstadt, who was kind enough to relieve me of the 
troublesome business of organization and editorial work during my present journey of convalescence. 
Finally I must mention that the editor's responsibility refers only to the German text. Of the French 
edition which has entirely passed into the hands of the firm of Le Moult, I have no knowledge whatsoever. 
Araraquara, March 24th 1927. 
Dr. Adalbert Seitz 
Darmstadt. 
