GAME ANIMALS TO DISEASE IN AFRICA 19 
been somewhat of a mystery, namely, how it is that in some 
places there are great numbers of tsetse flies, although game 
and other animals of any kind are not to be found or are very 
scarce in these places. 
Also in Japan Dr. Pryer states that sand-flies have been 
found to feed upon the larvae of other insects, and suggests that 
other larger blood-sucking flies may do the same (‘ Sleeping 
Sickness Bulletin,’ Vol. 8, No. 81, pp. 419-20). 
The possibility also of tsetse and other blood-sucking flies 
being able to exist upon a diet of plant juices must not be lost 
sight of. Personally I am sceptical of the likelihood of such 
specialised insects as blood-sucking flies being able to breed 
until they have fed upon blood, but it is conceivably possible 
that they might exist upon such a diet, or upon nothing, with- 
out breeding for several months. Conversely, however, it must 
also not be forgotten that some butterflies whose natural 
food is honey and plant juices will feed greedily off dead 
carcases, even w T hen in an advanced stage of decomposition, and 
also on the dung of animals. 
Mr. R. C. F. Maugham, H.B.M. Consul of Lourengo Marques, 
in answer to a letter writes as follows : — 
4 1 have seen tsetse flies sucking vegetable juices on two 
occasions. The first was in swampy ground south of Shupanga 
Forest on the Zambesi in 1905, when the fly, a common Glossina 
morsitans , alighted on a stem of a young marsh grass ( Phragmites 
communis) and, as I watched it, deliberately inserted its proboscis 
and unmistakably sucked for a period of about two minutes 
and a half. At this stage I caught it, and found on exami- 
nation that it was partly full of the moisture from the plant. 
‘ On the second occasion, in 1908, 1 was taking an expedition 
from the coast of this province at Ibo to Lake Nyassa. There 
is one district which my caravan traversed, between M’salu 
and Fort Dom Luiz Fillipe I believe, where for nearly three days, 
in absolutely gameless and practically waterless country, 
Glossina morsitans occurred in such numbers as to be a source 
of the greatest annoyance. Halting at midday on one occasion 
during this portion of my journey, one of my servants, who 
had bought some green sugar-cane on the way and was gnawing 
it, left the fragment close to my chair whilst the table was being 
