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THE AUSTRALIAN NATURALIST. 109. 
ja iraeeteaeneaner 
We have a number of Water Bugs, the largest of which 
(Belostoma indicum) was commonly caught during May and 
June last about electric lights in Sydney and the suburbs. 
It is a large brown, oval-shaped creature, with large eyes, 
and short, stout, sucking beak, and at night may leave the 
water and’ fly to other pools. It is predaceous, and attacks, 
other water insects, and éven small fish. Our common Syd- 
ney ‘‘Water Boatman’’ is Voriza geoffreyt, and our ‘Back. 
Swimmer”’ is Hnithares bergrothi, though allied species are. 
also to be found. There is a slaty or brown flat bug, about 
an inch long and resembling a piece of dead leat, which 
crawls with sluggish movements in the mud and leaves of 
the pools. This is well named the ‘‘Water Scorpion’? (Vepa 
tristis), as its appearance suggests some venomous form. It 
preys on other insects, which it captures in the large nipper- 
shaped front pair of legs. Behind is a long, slender siphon, 
ag long as the body, which is projected above water to take: 
in air. The wings are well developed, and when expanded 
the dull brown body is relieved by the brilliant brick-red 
colour of the upper surface of the abdomen in contrast. 
Hristalis tenax is the common Bee-fly of Sydney gar- 
dens, a fly that so resembles a bee in colour, shape and hum, 
as to deceive all who do not examine it closely. This com- 
mon fly is a cosmopolitan species, and, after its mimicry, 
interest centres in the curious larvae, which are known as, 
“rat-tailed larvae.’’ They live in water containing decaying 
vegetable matter. I have taken such larvae in a pool 3 inches. 
deep in a hollow on a fallen tree where a few dead leaves had 
accumulated, and their extremely long, slender tails were 
projected at the surface to take in air. These tails are tele- 
scopic, and can be projected according to the depth of the 
liquid some 3 or 4 inches, which is several times the length 
of the body. 
In conclusion, the Mosquitoes, which occur to one when- 
ever aquatic insects are referred to, cannot be more than men- 
tioned here. Their tiny wriggling larvae are familiar to all 
who have looked into pools by the roadside, in the bush, or, 
about the house, in flower pots, tins, or roof guttering where. 
water may collect. The fact of théir role in carrying disease 
has focussed much attention on the: group, and Australia has. 
her share of species. The Anopheles and certain other genera 
are capable of conveying malaria germs from man to man, 
and we have members of the first genus in Australia. Tho. 
Stegomyia fasciata, the ‘‘yellow -fever’’ intermediate host, is. 
also found in Queensland and Port Darwin, though fortun- 
ately the disease is not here. One of the common house and’ 
bush mosquitoes of N.S.W. and Queensland is Oulew fatigans, 
which has been shown to carry filariasis, and probably also 
Dengue fever. 
