33 
of Africa, including South Africa, about which I have no data, 
it has been reported from the whole of Europe, as far north 
as Lapland, from Northern and Central Asia, beginning with 
Syria and Persia, through China to Japan (1), from North 
Africa (Algiers) and from the islands surrounding Africa (Ma- 
deira, the Canary Islands, and, on the eastern side, Madagascar 
and Bourbon). During my twenty years of residence in North 
America, spent in collecting diptera and receiving collections 
from many other entomologists, I never met with a specimen 
of FE. tenax, until Nov. 5th 1875, when, to my great astonishment, 
I found one on a window in Dr. Hagen’s house in Cambridge, 
Mass. A year later (Oct., Nov. 1876), I observed several spe- 
cimens on the fences of Newport, R. I. In June 1877, I sailed 
for Europe, but I heard afterwards that during the same year 
the fly had become so common, that ,hundreds were caught.“ 
A few years later, the species was reported from nearly all 
the States of the Union, including California and Washington 
Territory; also from Canada (Montreal, common, as stated by 
Mr. Caulfield in Canad. Entom. 1884, p. 138). 
A communication made by the american Dipterologist 
Dr. Williston (Synopsis. of the N. Am. Syrphidae 1886, p. 161) 
proves that the invasion has gone, not from the Atlantic border 
to the West, as one might have expected, but on the contrary, 
from West to East. Dr. Williston had seen a specimen of 
E. tenax hidden among a lot of duplicates in Prof. Riley’s col- 
lection, bearing a label S. Louis, August 1870. Upon drawing 
Prof. Riley’s attention to the fly (which the latter did not pre- 
viously know by name), he was assured that the species had 
long been familiar to Mr. Riley in outhouses about S. Louis. 
The surprising rapidity, however, with which the species spread 
along the Atlantic coast, soon after its first appearance, renders 
(1) The occurrence of L. tenax of Japan is of very long standing, An 
Encyclopedia, compiled in 1713 contains a mention of the fly and its larva, 
,living in ordures*, which proves that the people did not confound it with the 
bee. They called it ,bunbun*, from the humming sound it produces. (Commu- 
nication of Mr. Kumagusu Minakata in litt.; compare above, p, 20.) 
oe 
