PSY CEE: 
THE YELLOW FEVER FLY. 
BY HERMANN AUGUST HAGEN, CAMBRIDGE, MASS. 
It is not without precedent that certain 
facts or observations in natural history sud- 
denly acquire a great fame, go more or less 
over the whole scientific world, and are 
forgotten with wonderful quickness, when 
they have been found out not to be true. 
Some twenty-five years ago the history of 
the famous yellow fever fly was every- 
where told and largely analyzed. It seems 
that the height of its glory was in 1855; 
1 say it seems, as I have been unable 
to see any account or even any mention 
of it in a scientific publication or a news- 
paper. 
nected with such publications in former 
times, assure me that the matter was at 
that time much spoken of in periodicals, 
but that they cannot give any quotation of 
an article. Upon application to the well 
known physician, Dr. St. Julian B. Rav- 
enel, in 8S. Carolina, I obtained the answer 
that although the Doctor had almost for- 
gotten about it, yet with some effort of 
memory he recalled that during the epi- 
demic at Norfolk in 1855, a fly appeared 
in swarms, which the people there said 
had never been seen before, and which they 
ealled the yellow fever fly. The Doctor 
had sent some of them to the late Prof. L. 
Agassiz for examination; but these are 
not now to be found in the collection of 
Gentlemen, who were largely con- 
the museum. The Doctor, however, states 
that he has since found the same fly in 
Charleston, S. C., in dark, close places, 
even in perfectly healthy seasons, and thinks 
that it only becomes immeasurably multi- 
plied in the dirt and filth of all kinds pro- 
duced by pestilence. It has never been 
observed in Charleston during epidemics. 
This is the only direct information I was 
able to obtain. The collection bought by 
the Museum of Comparative Zoology from 
Prof. Loew, contains one specimen, col- 
lected in 1848 in New Orleans by the late 
Prof. Schaum, and three others, one marked 
as the yellow fever fly. The species has 
never been described. It belongs to Sciara, 
and a careful examination of the descrip- 
tions of all the species quoted in Baron Os- 
ten Sacken’s new catalog of N. A. diptera, 
shows that none of them belong to this 
species. I was not able to compare the 
descriptions of Sciara nigra Wied. 
The fact that the species appeared in 
swarms is also new. A list of swarms 
of diptera, given by Prof. Weyenbergh 
(Tijdskr. vy. Eutom., 1861), records 29, 
but none of Sciara. 
I believe that a description of the species 
is very desirable, so that its former curious 
history, and the fact of its swarming, may 
not be lost. 
