XXVI 
FLIES AND SLEEPING SICKNESS 
321 
animals it may be worth. mention that a fossil biting- 
fly has been discovered in the Miocene shales of 
Florissant, Colorado. This fly had a remarkably long 
and strong proboscis. Professor T. D. A. Cockerell 
recognised it as a tsetse-fly. 
“ The mouth parts are preserved, as also the body, 
wings, and legs, all agreeing so well with the modern 
tsetse-fly that the generic separation is impractical )le.” 
Tacked on to the description of this fossil is the 
subjoined suggestion by Professor Osborn :— 
The former existence of a Tsetse-fly in America is of 
peculiar interest as having a possible connection with 
the disappearance of some of 
the Tertiary mammalia. 
The tsetse fly Glossina pal- 
pal'is assumed great importance 
when it was discovered (1903) 
to be capable of conveying 
trypanosomes, the parasites 
which cause sleeping sickness. 
A Fossil Tsetse Fly. 
The thorax is a little distorted ; 
tlie small shell near the right 
wing is a planorbis. 
In the dry terms of a medical 
text-book this disease is defined 
as :—An endemic disease of 
different parts of Equatorial Africa, characterised by a 
gradually increasing lethargy, mental and physical 
degeneration, elevated evening temperature, rapid pulse, 
progressive emaciation, and tremors ; after running an 
acute or chronic course, it almost invariably terminates 
fatally. 
This is a dreadful indictment against any disease, but 
it is more remarkable than appears from this carefully 
drawn up statement of claim. Although Sleeping 
Sickness was known to medical writers early in the 
nineteenth century, the disease did not really attract 
much attention until it was detected in Uganda in 
1900 by Dr. J. Howard Cook of the Mission Hospital, 
Mengo. The disease spread very rapidly along the 
north shore of the Victoria Nyanza, especially in 
