m 3 1
2 2 BRITISH BLOOD-SUCKING FLIES NEMATOCERA—CULICIDAE 23
Most of the records of C. molestus in this country are of adults only, so that
little can be said regarding its natural breeding-places. In France, however,
it is said to be specially addicted to cess-pools and septic tanks, though it does
occur in other types of breeding place such as those more favoured by C.pipiens.
Paradoxically, although C. Dwlestus is capable of carrying on its existence
without a blood-meal, it is far more bloodthirsty than C. pipiens ; it not only
feeds on birds but also attacks man very readily—usually indoors and at night.
From the now established fact that house-gnats exist in two distinct forms,
one man-biting and one man-ignoring, a conclusion of practical importance
may be drawn : that is, that in this country control measures against them are
entirely unnecessary unless the (fortunately very localised) C. molestus is present.
Culex apicalis Adams
Apart from the two common house-gnats, this is the only member of the
genus Culex occurring in these islands. It is similar in appearance to C.
pipiens, but may be distinguished very readily by the position of the white
bands of the abdomen, which are placed on the hind instead of the front margin
of each segment. The species is rare in Britain ; a few examples have been
captured in the highlands of Scotland and single larvae have been taken at
Hayling (Hants) and Easthampstead (Berks).
C. apicalis is widely distributed in Europe and North America, its breeding
places being similar to those of C. pipiens. The females do not hibernate in
dwellings, but have been found doing so in crevices between stones ; they do
not attack warm-blooded vertebrates, but have been observed biting frogs and
snakes, as is the case with some other nearly related species in other parts of
the world.
Genus ORTHOPODOMYIA Theobald
The unusually short fourth segment of the front tarsus is regarded as the
most important diagnostic feature distinguishing female mosquitoes of this
genus from others, but the single British species is more easily recognised by
its peculiar and conspicuous ornament.
The species of Orthopodomyia are few in number and mostly tropical in
distribution. All of them breed either in tree-holes or in the water collected
in the axils of leaves of various plants, and none of them is known to bite man.
Orthopodomyia pulchripalpis Rondani
(Plate 12)
This is, perhaps, the most handsome of all our native mosquitoes. The
beautiful pattern of the thorax, consisting of sharply defined fine white lines
on a dull black ground, should make its identity quite unmistakeable, while
further distinctive features are the white band across the middle of the proboscis
and the sharply contrasted black and white colouring of the whole body ; the
broad white rings on the hind tarsi spread across the joints.
All the examples of this insect taken in England have been reared from
larvae ; it is a remarkable fact that it has never been seen on the wing and was
not known to occur with us until the discovery of its larvae in Epping Forest
in 1920. The available records suggest that it has a very local distribution,
as it has so far been found only in a few places in London and the home counties,
and at Cambridge and Hayling Island, but when searched for it will probably
be found to be widely spread in the south and midlands of England.
O. pulchripalpis breeds exclusively in the water which collects in holes in
trees, and chiefly in those holes which contain a fair volume of water
for a considerable period of the year, the water bemg dark brown in colour
There is probably only one generation in the year. The species has been kept
under observation at the Molteno Institute, Cambridge, a supply being maintained
in a hollow tree-trunk set up in the grounds. The observations made
have been thus summarised by Tate :
" Larvae of O. pulchripalpis are usually present all the year round, and
are especially abundant in July and August. The fourth-instar larvae may
over-winter in the reservoir, and even if these larvae are brought indoors
and kept in a warm room they will not pupate until the following spring.
Although the imagines live for several weeks in captivity if fed on raisins
or apple they do not breed. The females, in captivity, would not bite man,
birds, toads or invertebrates such as earth-worms or slugs."
Genus TAENIORHYNCHUS Lynch
The species of this genus have the abdomen of the female blunt-tipped and
the claws simple as in Theobaldia and Culex, the chief distinctions from these
genera (so far as the adult female is concerned) being in microscopic details.
The genus, however, is sharply distinguished from other mosquito genera by
the remarkable adaptations of the larvae for aquatic life, as noted in the account
of the single British species which follows.
Taeniorhynchus richiardii Ficalbi
(Plate II)
In general naked-eye appearance there is nothing strikingly distinctive
about this nisect, its size and tawny-brown colour reminding one very much of
Cuhxpipiens, the common house-gnat ; abraded examples of these two species
might indeed be very easily confused. The distinctive features of T. richiardii
are however, quite easily appreciated, especially if the insect be examined
u n d j a hand-lens. The upper surface of the abdomen lacks transverse white
bands ; the tarsi are ringed—even though somewhat inconspicuously—with
creamy-white, the iirst segment having a ring in the middle as well as one at
the base the others at the base only ; and the veins of the wings are clothed
with scales which are unusually broad, many of them being pale in colour
while others are dark, giving the wing a peppered appearance.
i . richtardu is locally common in England, having been found in most of
the counties where collectors have searched for it and occurring as far north as
Durham, as well as in Belfast, County Down and County Wicklow in Ireland ;
present, however, there are no records for Wales or Scotland.