4 
WORK IN' THE UNITED STATES 
Cams Sterne), will be found in the present “Record,” Part II, Chapter XV. In 
Chapter XVI I have given a Characterization of Loew as a Dipterologist. 
A complete list of Loew’s publications on the dipterous fauna of America 
will be found in my “Catalogue of North American Diptera,” edit. 2, 1878, 
p. xxxiv-xxxvi. 
Dr. II. Loew, with whom I had had a short correspondence pre¬ 
viously (about 1850-1851) concerning Trochobola annulcita Linne, 
which was soon interrupted, showed a great eagerness to renew it 
when he heard of my appointment to the United States. I readily 
fell in with his wishes, in the hope of utilizing his well-known 
working-power in the interest of American dipterology. After a 
rather long, ^wasLtentative correspondence, during the first years 
of my residence in America, about the mode and conditions of 
our proposed co-operation, we came to the following agreement: I 
promised to send to Loew as much material as I could, on the con¬ 
dition, however, that he should consider the collection thus gradu¬ 
ally accumulating in his hands not as his property, but as a trust. 
My purpose was, by this means, to form a collection of North Amer¬ 
ican Diptera containing the type-specimens described by Loew, as 
well as specimens determined by him from earlier authors, and, 
as the case might be, an abundant supply of as yet undescribed 
and undetermined specimens. Such a collection I expected, 
sooner or later, to be brought back to the United States, in order 
to form a solid foundation for the further study of the American 
fauna. This scheme enabled me to receive without stint the 
numerous contributions in collections and specimens which were, 
most generously, put at my disposal by different collectors during 
my long residence in the United States. As will be shown in 
the sequel, this scheme came to a successful conclusion, princi¬ 
pally in consequence of the generous intervention of Prof. Louis 
Agassiz. In 1877 this collection, containing (according to Loew’s 
estimation) about 1850 species described by himself, 330 species 
described by earlier authors, and a large number of undescribed 
species, forming a total of about 3000 species, came back to the 
I nited States and was safely housed in the Museum of Compara¬ 
tive Zoology in Cambridge, Mass. At the same time Loew received 
from the Museum a liberal remuneration for his work on the col- 
