The Ants of the Baltic Amber. 
By 
William Morton Wheeler Ph. D. 
Professor of Economic Entomology, Harvard University. 
Seven years ago the late Professor Richard Klebs of Königsberg 
requested me to study and describe the ants in his beautiful collection 
of amber inclusions, and, on my consenting, forthwith sent me all of 
his specimens, 1405 in number. A year later Professor A. Tornquist 
generously sent me the entire Formicid collection of the Königliche 
Bernsteinsammlung des Geologischen Instituts of Königsberg. This 
remarkable collection comprises 7819 specimens, exclusive of Gustav 
Mayr’s types, which were alsoloanedme for reexamination, In addition 
to this material I have been able to study three sm aller collections. 
Monsieur G. Severin loaned me the collection of the Brussels Museum, 
comprising 19 specimens, Dr. Richard Heymons that of the Berlin 
Museum, comprising 115, and Mr. William Haren of St. Louis, Missouri, 
his private collection of 169 specimens. Thus I have been able to 
study altogether 9527 ants from the Baltic amber. I wish to express 
my indebtedness to all these gentlemen for the loan of so many speci- 
mens, and, especially to Prof. Tornquist for permission to retain so 
much valuable material in my possession for several years. I sincerely 
regret that the work has been so unduly protracted and so frequently 
interrupted by urgent professional duties. This regret is the deeper, 
because Prof. Klebs, who first interested me in the subject and gave 
me much friendly assistance in the early part of the work, did not 
live to see it completed. 
As many previous students have remarked, the study of the 
insects embedded in the amber is frought with many and peculiar 
difficulties. Although some specimens are as beautifully clear as if 
they had just been carefully dehydrated and embedded in Canada 
balsam by an expert histologist, most of the specimens are either in 
awkward positions or have portions of the body concealed beneath 
milky or silvery films or air-bubbles or obscured by disconcerting 
cracks, or the highly refractive medium gives rise to distorted images 
which can be corrected only by repeated examination in the most 
various lights or by careful comparison of numerous specimens of the 
same species. It is, of course, possible to dissolve the amber away 
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Schriften d. Physikal.- Ökonom. Gesellschaft. Jahrgang LV. 
