UHBSniAi IB ‘ 
TABLE OF CONTENTS 
PART PIRST 
Introduction. 1 
I Work in St. Petersburg (1854-1856). 1 
II Work in the United States (1856-1877). 3 
III Work in Europe (principally in Heidelberg) since 1877 . 9 
Note on the Rise of the Order Diptera in Public Estimation during 
the Nineteenth Century.25 
PART SECOND 
Twenty-four Chapters on Historical, Biographical, Critical, and 
purely Entomological Subjects connected with my Work 28 
Preface.28 
I On the Beginnings of my Relations with Loew, with some 
Remarks on the general Character of our Correspondence 29 
This Chapter is illustrated by a facsimile of Loew’s hand¬ 
writing. 
II On Loew’s Reception of my first Work on Tipulidae . . 32 
III Robert Kennicott.35 
A notice on the services rendered to me by this American 
naturalist who collected for me many Diptera, especially in the 
northwestern region of the British possessions in North America. 
IV Short Notices of Benjamin D. Walsh and Homer F. Bassett, 
Correspondents in my Work on Cynipidae ; of Dr. 
William Le Baron (1814-1876), Geneva, Illinois; and of 
Mr. E. Foreman, Washington, D. C.38 
V A Contribution to the History of the Entomological Society 
of Philadelphia.41 
An account of the very modest beginnings of this Society, due 
to the co-operation of Dr. Th. B. Wilson, and especially of Mr. 
