274 
Tse-tse- 
-INSECTS.- 
-Pjiytalmia. 
appe.ai-s fortunately to be confined to particular districts, 
and is usually found on hills, plains being free from it; 
it is not much larger than the common house-fly, but 
longer and of a blacker colour, with bars on its body. 
The attack of ten or a dozen is said to cause the death 
of a horse; to oxen its attack is equally fatal. The 
Tse-tse also at times attacks man ; but no danger fol- 
lows — in fact, no more than from the bite of a flea, 
Man and all wild animals appear to escape with impu- 
nity ; but tlie losses' experienced through its attack on 
domestic animals are quite appalling. 
Dr. Livingston describes the Tse-tse as remarkably 
alert ; it avoids dexterously all attempts to capture it 
with the hand at mid-day. In the cool of the morning 
and evening it is not so agile. He says that its peculiar 
buzz, when once heard, can never be forgotten by any 
ti’aveller whose means of locomotion are domestic ani- 
mals; ‘'for it is well known that the bite of this poisonous 
insect is certain death to the ox, horse, and dog. In 
this journej', though we were not aware of any great 
number having at any time lighted on our cattle, we 
lost forty-three fine oxen by its bite. We watched the 
animals carefully, and believe that not a score of flies 
were ever upon them. 
“ The mule, ass, and goat enjoy the same immunity 
from the Tse-tse as man and the game. Many large 
tribes on the Zambesi can keep no domestic animals, 
except the goat, in consequence of the scourge existing 
in their country. Our children were frequently bitten, 
yet suffered no harm ; and we saw around us numbers 
of zebras, buffaloes, pigs, pallahs, and other antelopes, 
feeding quietly in the very habitat of the fly. There 
is not so much difference in the natures of the horse 
and zebra, the buffalo and ox, the sheep and antelope, 
as to afford any satisfactory explanation of the pheno- 
menon. Is not man as much a domestic animal as a 
dog ? The disgust which the Tse-tse shows to animal 
excreta, is turned to account by some of the doctors. 
They mix droppings of animals, human milk, and some 
medicines together, and smear the animals that are 
about to pass through an infested district. This, though 
a preventive at the time, is not a permanent 
protection. Inoculation does not insure im- 
munity, as animals which have been slightly 
bitten in one year may perish by a greater 
number of bites in the next. It is probable ^ 
thatrwith the increase of guns, the game, as 
happened in the south, and the Tse-tse deprived 
of food, may become extinct simultaneously with 
the larger animals. The ravages it commits 
are sometimes enormous. Sebituane once lost 
nearly the entire cattle of his tribe, amounting 
to many thousands, by unwittingly intruding 
upon the haunts of this murderous insect.” 
We must refer briefly to the great benefits derived 
by man through the agency of these insects. Diptera 
are the great removers or scavengers of all 
putrid animal and vegetable substances. No 
sooner does an animal or plant die and begin 
to decay, than it is resorted to by hosts of Diptera 
which deposit their eggs immediately upon it ; and so 
quickly are these hatched and the larvae full grown, that 
a successive generation of flies continue to subsist upon 
the same food, until it is entirely consumed, and thus 
the earth is cleared of all offensive, and what would 
probably prove infectious and injurious matter. Ex- 
crement of all kinds, is in a great degree, removed 
through their agency. 
We have only space left briefly to allude td some of 
the more remarkable forms which occur in different 
genera of Diptera. In the genus Asilus some species 
from Brazil so closely resemble species of bees peculiar 
to the same country, that it requires an amount of 
entomological knowledge to distinguish the difference; 
other species of Diptera exactly resemble wasps, into 
whose nests they probably enter, being parasitic on the 
larva of the wasp. Species of the genus VoUucella, 
parasitic upon Humble bees, very' closely resemble the 
bees themselves. 
One genus, Diopsis (see Plate 11, fig. 7), may be 
mentioned as possessing a very remarkable peculiarity 
of structure; the eyes in the species of this genus are 
situated on pedicels half the length of the body of the 
fly. These pedicels arise from the sides of the head, at 
the usual situation of the eyes in ordinary species ; tlie 
antennse are situated near the eyes, one being on each 
foot-stalk or pedicel near to the eye which forms its 
Fig. 175. 
Achias maculipennis. 
extremity'. These species are found in Africa, India, 
and in the islands of the Eastern archipelago. Fig. 
175 shows a species of an allied genus Addas maculi- 
Phytalmiii cervicornis, greatly magnified — a, male; h, female. 
peunis^ and fig. 176, a, two outlines of a remarkable 
species of the genus PhytaJmia described by AV. W. 
