_, small, grey and quietly persistent, carries
the malaria that has laid our army low. _Culex_, larger and more noisy,
trumpets his presence in the night watches: but the mischief he causes
is in inverse ratio to the noise he makes. _Stegomyia_, host of the
spirium of yellow fever, is also here, but happily not yet infected; not
yet, but it may be only a question of time before yellow fever is
brought along the railways or caravan routes from the Congo or the
rivers of the West Coast, where the disease is endemic. There for many
years it was regarded as biliary fever or blackwater or malaria. Now
that the truth is known a heavier responsibility is cast upon the
already overburdened shoulders of the Sanitary Officer and the
specialists in tropical diseases. _Stegomyia_, as yet uninfected, are
also found in quantities in the East; and with the opening of the Panama
Canal, that links the West Indies and Caribbean Sea, where yellow fever
is endemic, with the teeming millions of China and India, may materially
add to the burden of the doctors in the East. Living a bare fourteen
days as he does, infected _stegomyia_ died a natural death, in the old
days, during the long voyage round the Horn, and thus failed to infect
the Eastern Coolie, who would in turn infect these brothers of the West
Indian mosquito.

Fortunate it is in one way that _anopheles_ is the mosquito of lines of
communication, of the bases, of houses and huts and dwellings of man,
rather than of the bush. Our fighting troops are consequently not so
exposed as troops on lines of communication. For this blessing we are
grateful, for lines of communication troops can use mosquito nets, but
divisional troops on trek or on patrol cannot. Soon we shall see the
fighting troops line up each evening for the protective application of
mosquito oil. For where nets are not usable it is yet possible to
protect the face and hands for six hours, at least, by application of
oil of citronella, camphor, and paraffin. Nor is this mixture
unpleasant; for the smell of citronella is the fragrance of verbena from
Shropshire gardens.

Least in size, but in its capacity for annoyance greatest, perhaps, of
all, is the sand fly. Almost microscopic, but with delicate grey wings,
of a shape that Titania's self might wear, they slip through the holes
of mosquito gauze and torment our feet by night and day. The three-day
fever they leave behind is yet as nothing compared to the itching fury