19 
Be this as it may, the species o£ Tsetse fly in question is 
common enough in the vicinity of Freetown, and for some 
reason always seems to occur along the beds of streams, where 
it is fond of sitting on stones projecting from the water : it also 
abounds in mangrove thickets fringing the mouths of streams, 
close to the sea-shore. On one occasion I found it among bushes 
on the hill-side below Wilberforce, settling on stones in a small 
stream barely a yard in width. This fondness for running water 
is curious, and may possibly be due to the survival of an ancient 
habit by which the fly at one time obtained its food, as it 
probably does still in other parts of Africa. For instance, some 
twenty specimens of Glossiua morsitans, presented to the Museum 
by Mr. Christopher Heseltine, were obtained by the donor on 
the Tzende River, North-East Transvaal. But near Freetown j 
since, as has just been pointed out, big game is practically non- 
existent, there would seem to be little encouragement for the fly 
to wait for animals coming down to drink. 
The Tsetse fly is remarkably active and exceedingly difficult 
to catch, but persistently returns to the same spot ; it bites, and 
sucks human blood freely. 
Residents in Freetown and the vicinity often suffer from "Tumba" 
Flv 
a kind of painful boil, produced by a maggot which lives beneath 
the skin. I was informed that this was produced by the "sting" 
of an insect known as the " tumba " fly, but what the insect was 
like no one could tell me, although many had seen the grub after 
extraction. There was evidently much confusion on the subject, 
though some persons seemed to consider that the maggot was the 
offspring of a horse-fly r , which, from what is known of the life- 
history of the Tabanidas (the family to which horse-flies belong), 
was exceedingly improbable. It was said that dogs and pet 
monkeys are often afflicted in the same way, and 1 therefore 
expected that the mischief-maker would prove to be a warble- 
fly (Family GEstridse), allied to Dermatobia cyaniventris — a species 
with similar habits which occurs in Central and South America. 
In this, however, I was mistaken. A lady (" Sister Dorothy," 
of the Princess Christian Hospital, Freetown), finding that 
a small monkey belonging to her was infected with "tumba " fly 
maggots, kindly lent the animal to me, with the result that 
I obtained from it no less than 11 larvae and pupae, some of 
