Chapter XXIX: Section C: Proboscis short, not formed for (1)

piercing _Corethrina._
Metatarsus longer than first tarsal
joint _Corethra_, Linnæus.
Metatarsus shorter than first tarsal
joint _Mochlonyx_, Ruthe.[391]

[391] Many other genera have been created; these will be found in my catalogue of _Culicidæ_ in my “Monograph of the Mosquitoes of the World,” 1901–10, 5 vols., in my “Novæ Culicidæ,” family _Culicidæ_, Genera Insectorum, etc.

NOTES ON THE DIFFERENT GENERA.

Sub-family. *Anophelina.*

The following Anophelines have been recorded as malaria carriers:--

*_Anopheles maculipennis_, Meigen.
_Anopheles bifurcatus_, Linnæus.
*_Myzomyia funesta_, Giles.
_Myzomyia lutzii_, Theobald.
*_Myzomyia rossii_, Giles.
_Myzomyia listonii_, Liston.
_Myzomyia culicifacies_, Giles.
_Pyretophorus superpictus_, Grassi.
*_Pyretophorus costalis_, Loew.
_Pyretophorus chaudoyei_, Theobald.
*_Cellia argyrotarsis_, Robineau Desvoidy.
_Myzorhynchus pseudopictus_, Grassi.
_Myzorhynchus barbirostris_, Van der Wulp.
_Myzorhynchus sinensis_, Wiedemann.
_Myzorhynchus paludis_, Theobald.
_Myzorhynchus mauritianus_, Grandpré.
_Neocellia stephensii_, Liston.
_Neocellia willmori_, James.
_Nyssorhynchus theobaldii_, Giles.
_Nyssorhynchus fuliginosus_, Giles.
_Nyssorhynchus annulipes_, Walker.

Those marked with an asterisk (*) also carry the larvæ of _Filaria bancrofti_, as also do _Myzorhynchus minutus_, Theobald, and _Myzorhynchus nigerrimus_, Giles.

Genus. *Anopheles*, Meigen.

“Syst. Beschr. Europ. zwei. Ins. I,” 1818, ii, p. 2, Meigen; “Mono.
Culicid.,” 1903, i, p. 191; iii, p. 17; and 1910, v, p. 3, Theobald.

This genus contains a few large species found either in temperate
climates or in hills and mountains of warm climates. The type is the
European and North American _A. maculipennis_.

_A. maculipennis_, Meigen. This species and _A. bifurcatus_ are
malaria carriers. True Anopheles only occur in Europe, North America,
the North of Africa and in the mountains of India, and one has been
found by Bancroft similar to _A. bifurcatus_ in Queensland. They are
easily told by the absence of scales on thorax and abdomen, and by
the rather densely scaled wings with lanceolate scales.

Genus. *Myzomyia*, Blanchard; *Grassia*, Theobald.

_Comp. rend. heb. Soc. Biol._, No. 23, p. 795, Blanchard; “Mono.
Culicid.,” 1910, iii, p. 24; v, p. 16, Theobald.

This genus occurs in Asia, Africa and South America, Europe and East
Indies. The type is _M. funesta_, Giles, found in Central and West
Africa. Although structurally there is not much difference between
this genus and Anopheles, they differ greatly in appearance, and
there are usually a few narrow curved thoracic scales projecting over
the head, whilst the wing scales are much smaller in proportion,
and the wings more uniformly spotted, always so along the costa.
_Funesta_ and _lutzii_ are undoubtedly malaria bearers and also
_rossii_.

Genus. *Neomyzomyia*, Theobald.

“Mono. Culicid.,” 1910, v, p. 29.

A single species only occurs in this genus, _N. elegans_, James, from
India. In this genus, which is near to Myzomyia, the fourth long vein
is very near the base of the third, and there are outstanding scales
on the prothoracic lobes, and there is a marked tuft of dense scales
at the posterior angles of the head.

Genus. *Cycloleppteron*, Theobald.

“Mono. Culicid.,” 1903, ii, p. 312; 1903, iii, p. 58; 1910, v, p. 33.

Two common species only occur in this genus, _C. grabhamii_, Theob.,
from Jamaica, and _C. mediopunctatus_, Theob. (Lutz., ms.), from
South America. The chief character is the presence of large black
inflated pyriform scales on the wings. The palpi are densely scaled.
Neither have been shown to be malaria bearers.

Genus. *Feltinella*, Theobald.

“Mono. Culicid.,” 1907, iv, p. 56.

A single species, so far only found in this genus. The basal lobes of
the male genitalia of two segments, the prothoracic lobes with dense
outstanding scales.

The species, _F. pallidopalpi_, Theob., occurs in Sierra Leone.

Genus. *Stethomyia*, Theobald.

“Mono. Culicid.,” 1903, iii, p. 13; 1907, iv, p. 59; 1910, v, p. 35.

Four species occur in this marked genus--one _S. nimba_, Theob., from
British Guiana and Para, another _S. fragalis_, Theob., from the
Malay States, _S. culiciformis_, James and Liston, from India, and
_S. pallida_, Ludlow, from India.

The former may be a malaria carrier, for Dr. Low says: “Malarial
fever is got amongst the Indians and often of a severe type. In
that connection it is interesting that in the interior, at a place
called Corato, I got an entirely new Anopheles in large numbers.” The
genus is easily told by its unornamented wings, flat head scales,
mammillated prothoracic lobes and long thin legs.

Genus. *Pyretophorus*, Blanchard; *Howardia*, Theobald.

_Compt. rend. heb. Soc. Biol._, No. 23, p. 705, Blanchard; _Journ.
Trop. Med._, v, p. 181; and “Mono. Culicid.,” 1903, iii, p. 13; 1910,
v, p. 36, Theobald.

Forty-four species come in this genus, of which _Anopheles costalis_,
Loew, is the type.

This genus is found in Africa, India, Europe and in Australia. Three
species are proved malaria bearers, namely, _P. costalis_, Loew, _P.
chaudoyei_, Theob., and _P. superpictus_, Grassi. Members of this
genus can be told by having narrow curved thoracic scales, hairy
abdomen, and much-spotted wings.

Genus. *Myzorhynchella*, Theobald.

“Mono. Culicid.,” 1907, iv, p. 78.

In this genus the thorax has distinct, narrow curved scales, and the
abdomen is hairy, the wing scales broad and lanceolate, and the head
with broad scales not closely appressed, but not forked or fimbriated.

Five species are known: _lutzi_, Cruz; _parva_, Chagas;
_nigritarsis_, Chagas; _tibiomaculata_, Neiva; _gilesi_, Neiva; and
_nigra_, Theobald. They are all recorded from Brazil, and _nigra_
also from Mexico.

Genus. *Manguinhosia*, Cruz, in Peryassu.

“Os Culicideos do Brazil,” 1908, p. 112.

A single marked species from the Brazils. The thorax has piliform
curved scales, and some narrow curved and flattened ones on the
sides. Abdomen pilose, except the last three segments which are
scaled. No tufts of scales on posterior femora.

Allied to Lophoscelomyia, but at once told by the absence of scale
tufts on the hind femora. _M. lutzi_, Cruz, Brazil.

Genus. *Chrystya*, Theobald.

“Rep. Sleeping Sickness, Roy. Soc. Eng.,” 1903, vii, p. 34.

A very marked genus in which the hairy abdomen has very long, dense,
hair-like, apical, scaly tufts to the segments. A single species only
so far known, _C. implexa_, Theobald, from Africa (Uganda, Sudan,
etc.).

Genus. *Lophoscelomyia*, Theobald.

_Entomologist_, 1904, xxxvi, p. 12.

A single species only, from the Federated Malay States. The hind
femora have dense, apical scale tufts; the thorax long, hair-like
curved scales; abdomen pilose, except the last two segments which are
scaly; wings with broad, blunt, lanceolate scales.

Genus. *Arribalzagia*, Theobald.

“Mono. Culicid.,” 1903, iii, pp. 13 and 81; and 1910, v, p. 48.

Two species only occur, found in South America. The thorax and
abdomen have scales and hairs respectively, as in Pyretophorus, but
the abdomen has in addition prominent lateral apical scale tufts
to the segments and a scaly venter. Wings with membrane tinged in
patches and wing scales bluntly lanceolate and very dense. The
type is _A. maculipes_, Theob. found in Trinidad and Brazil; _A.
pseudomaculipes_, Cruz, also in Brazil.

Genus. *Myzorhynchus*, Blanchard; *Rossia*, Theobald.

_Compt. rend. heb. Soc. Biol._, 1902, No. 23, p. 795, Blanchard;
_Journ. Trop. Med._, 1902, p. 181, Theobald; “Mono. Culicid.,” 1903,
iii, p. 84; 1907, iv, p. 80; 1910, v, p. 49.

A very marked genus of large, dark, densely scaled species, found
in Europe, Asia, Africa and Australia. The thorax with hair-like
curved scales; the abdomen with ventral and apical scales, and a
median ventral apical tuft, and with very densely scaled palpi in
the female, and densely scaled proboscis. It seems to be mainly an
Asiatic and East Indian genus, but three species occur in Africa and
one in Australia. They are mostly sylvan species and bite severely.

Fourteen species are known. Five are malaria carriers (_vide_ list,
p. 566).

Genus. *Nyssorhynchus*, Blanchard; *Laverania*, Theobald.

“Mono. Culicid.,” 1910, iii, p. 14; v, p. 55, Theobald; _Compt. rend.
heb. Soc. Biol._, No. 23, p. 795, Blanchard.

A group of small, closely allied species found in Asia, Africa and
Australia, twelve out of the twenty species coming from India.

The thorax is covered with narrow curved and spindle-shaped scales,
abdomen with small, flat or narrow curved dorsal scales, especially
on the apical segments or in patches; the legs are always banded or
spotted with white, and the tarsi have as a rule one or more pure
white segments. (This banding and spotting is of no generic value,
however.)

The species show considerable seasonal variation. The type of the
genus is _N. maculatus_, Theobald.

Three are malaria carriers (_vide_ list, p. 566).

Genus. *Cellia*, Theobald.

“Mono. Culicid.,” 1903, iii, p. 107; 1910, v, p. 67.

Very marked Anophelines, with densely scaly abdomens, the scales
irregularly disposed on the dorsum and forming dense lateral tufts;
thorax with flat spindle-shaped scales; palpi densely scaled and also
the wings.

The type of the genus is the African _C. pharoensis_, Theob. It is
represented in Asia by _C. kochii_, Dönitz; in West Indies and South
America by _C. argyrotarsis_, Desvoidy, and _C. bigotii_, Theob.; in
Africa by _C. squamosa_, Theob., etc.

_C. argyrotarsis_, Desvoidy, and _C. albimana_, Wiedemann, are
undoubtedly malaria bearers.

Genus. *Neocellia*, Theobald.

“Mono. Culicid.,” 1907, iv, p. 111.

Allied to Cellia, but has no lateral scale tufts. Three species
recorded from India.

Genus. *Kertészia*, Theobald.

“Ann. Mus. Nat., Hung.,” 1905, iii, p. 66.

This genus has the thoracic scales hair-like, except a few narrow
curved ones in front; abdominal scales long, broad and irregular.

A single species, _K. boliviensis_, Theob. from Bolivia.

Genus. *Manguinhosia*, Cruz.

The thorax has narrow hair-like curved scales and some broad straight
scales; others spatulate on the sides. Abdomen with fine hairs,
except the last three segments which are scaly. Tufts of scales on
the hind femora. Wing scales lanceolate.

The type is _M. lutzi_, Cruz, from Brazil.

Genus. *Chagasia*, Cruz.

“Brazil-Medico,” 1906, xx, pp. 20, 199.

This genus can at once be told by the antennal segments having many
dense scaly tufts. Type, _C. fajardoi_, Lutz, from Brazil.

Genus. *Calvertina*, Ludlow.

_Canadian Entomologist_, 1909, xli, pp. 22, 234.

The antennæ in this genus have outstanding scales on the second
segment, more appressed ones on the first. At least one abdominal
segment with long, flat, more or less spatulate scales. Type, _C.
lineata_, Ludlow, from Philippine Islands.

Genus. *Birónella*, Theobald.

“Ann. Mus. Nat. Hung.,” 1905, iii, p. 69.

At once told by the first submarginal cell being very small. Type,
_B. gracilis_, Theob. from New Guinea.

Sub-family. *Megarhininæ.*

Three genera occur in this marked sub-family; they are the largest
of all mosquitoes, and are very brilliantly coloured, and many have
tail fans. They occur in North and South America, Asia, Africa, and
Australia. The long curved proboscis is very marked. They are usually
spoken of as elephant mosquitoes; some are vicious blood-suckers at
times.

The three genera tabulate as follows:--

α. Palpi long in both sexes.
β. Last segment of ♀ palp round or
blunt as if broken Genus _Megarhinus_, R. Desvoidy.
ββ. Last segment of ♀ palp long
and pointed Genus _Ankylorhynchus_, Lutz.
αα. Palpi of female short of male
long.
Palpi of female not more than
one-third length of proboscis Genus _Toxorhynchites_, Theobald.

Genus. *Megarhinus*, Robineau Desvoidy.

“Mém. Soc. d’Hist. nat. de Paris,” 1827, iii, p. 412; “Mono.
Culicid.,” 1901, i, p. 215; 1903, iv, p. 163; 1907, iv, p. 128; 1910,
v, p. 89.

All large brilliant mosquitoes with long palpi in both sexes and, as
a rule, with a caudal fan of scales; the proboscis is long and bent.
They are all sylvan species, and are not so far recorded as biting
man.

Genus. *Toxorhynchites*, Theobald.

“Mono. Culicid.,” 1901, i, p. 244; 1903, iii, p. 119; 1907, iv,
p. 140; 1910, v, p. 95.

Differs from the former genus in that the female palpi are short. The
palpi may have one, two or three minute terminal segments. Banks’s
genus Worcesteria has three.

The elephant mosquito of India (_T. immisericors_), Walker, bites
very severely. They are sylvan species.

Sub-family. *Culicinæ*.

Genus. *Mucidus*, Theobald.

“Mono. Culicid.,” 1901, i, p. 268; 1910, v, p. 125.

This genus is so far confined to Australia, West and Central
Africa, India, East Indies and Malay Peninsula. They are all large
mosquitoes, easily told by the whole body being more or less covered
with long twisted scales, giving them a mouldy appearance, and the
legs densely scaled with outstanding scales; the wings with large
parti-coloured scales. The Australian _M. alternans_, Walker, occurs
in larval form both in fresh and salt water. The adults bite man.

Genus. *Psorophora*, Robineau Desvoidy.

“Mém. de la Soc. d’Hist. nat. de Paris,” 1827, iii, p. 412, R.
Desvoidy; “Mono. Culicid.,” 1901, i, p. 259; 1903, iii, p. 130; 1907,
iv, p. 158; 1910, v, p. 123, Theobald.

This genus is confined to the Americas and the West Indies. Several
species exist which can easily be told from Mucidus by the absence
of long twisted scales and the narrower wing scales. The legs are
densely scaled and the thorax ornamented with flat spindle-shaped
scales.

_P. ciliata_, Robineau Desvoidy, occurs in both North and South
America, and bites man.

Genus. *Janthinosoma*, Arribalzaga.

“Dipt. Arg.,” 1891, p. 52, Arribalzaga; “Mono. Culicid.,” 1901, i,
p. 253; 1903, iii, p. 124; 1907, iv, p. 152; and 1910, v, p. 118,
Theobald.

Hind legs only densely scaled; some of the hind tarsi are always
white. The venation is as in Culex. The abdomen is metallic and
iridescent. They all bite man and occur only in the Americas and West
Indies.

Genus. *Stegomyia*, Theobald.

“Mono. Culicid.,” 1901, i, p. 283; 1903, iii, p. 130; 1907, iv,
p. 170; 1910, v, p. 151.

This, the most important genus in the _Culicinæ_, can be told by the
head and scutellum being clothed with flat scales and the thorax with
narrow curved ones.

About forty species are known in this genus, occurring in Southern
Europe, Asia, Africa, Australia, the Americas, East and West
Indies, and on most oceanic islands. Many of them seem to be
vicious blood-suckers. They are mostly black and white mosquitoes,
and several seem to go by the name of tiger mosquitoes. The genus
contains the yellow fever mosquito (_S. fasciata_, Fabricius), the
only one that need be dealt with in detail here. The chief known
species tabulate as follows:--

A. Proboscis banded.
α. Legs basally banded.
Thorax brown, with scattered creamy-
white scales _annulirostris_, Theobald.
Thorax black, with narrow, curved
golden scales _periskelta_, Giles.
αα. Legs with basal and apical banding.
Fore legs with no bands; mid with
apical and basal bands on first and
second tarsals, hind with basal bands.
Thorax white in front, with a brown
eye-like spot on each side _thomsoni_, Theobald.
AA. Proboscis unbanded.
β. Legs basally banded.
γ. Abdomen basally banded.
Thorax with one median silvery-white
line _scutellaris_, Walker.
Thorax as above, but pleuræ with white
lines _pseudoscutellaris_, Theobald.
Thorax similar, but two white spots
near where line ends _gelebinensis_, Theobald.
Thorax with two median yellow lines
and lateral curved silvery lines _fasciata_, Fabr.
Thorax with two short median lines and
a white patch on each side _nigeria_, Theobald.
Thorax with large lateral white spots
in front, smaller ones by wings, two
narrow median lines and two posterior
sub-median white lines _lilii_, Theobald.
Thorax with a white *W*-shaped area in
front, a prolongation curved on each
side enclosing a brown eye-like spot _W-alba_, Theobald.
Thorax with white frontal median spot,
two large lateral spots, a small one
in front of the wings, a narrow median
white line and narrow sub-median ones
on posterior half. _Last two hind
tarsi white_ _wellmannii_, Theobald.
Thorax brown, with broad white line in
front extending laterally towards
wings, where they swell into a large
patch, a white line on each side just
past wing roots. _Last two hind tarsi
white_ _albipes_, Theobald.
Thorax with silvery white spot on each
side in front, small one over roots of
wings and white over their base. _Last
two hind tarsi white_ _pseudonigeria_, Theobald.
Thorax with two lateral white spots,
front ones the largest, a small median
one near head, two yellow median
lines, a short silvery one on each
side before the scutellum _simpsoni_, Theobald.
Thorax with silvery-white scaled area
in front and another on each side in
front of wings _argenteomaculata_, Theobald.
Thorax with median yellowish-white
line, a silvery patch on each side in
front of wings extending as a fine
yellow line to the scutellum, and
another silvery spot before base of
each wing _poweri_, Theobald.
Thorax with small grey-scaled area in
front of wing roots and three short
creamy lines behind _minutissima_, Theobald.
Thorax (?) denuded; abdomen black;
fifth segment with yellow basal band;
sixth unbanded; seventh, two median
lateral white spots; eighth, two basal
lateral white spots; second hind
tarsal nearly all white _dubia_, Theobald.
γγ. Abdomen unbanded.
First hind tarsal all white, second
basally white, last two dark. Thorax
chestnut brown, with a broad patch of
white scales on each side in front and
a median pale line _terreus_, Walker.
ββ. Legs with white lines as well as basal
bands.
Thorax brown, with white lines; abdomen
with basal bands _grantii_, Theobald.
βββ. Fore and mid legs with apical bands,
hind basal.
Fourth tarsal of hind legs nearly all
white _mediopunctata_, Theobald.
Mid metatarsi with basal pale banding,
base and apex of hind, also base of
first tarsal pale _assamensis_, Theobald.
ββββ. Legs unbanded.
δ. Abdomen basally banded.
Thorax with front half white, rest
bronzy-brown _pseudonivea_, Ludlow.
Thorax deep brown, with scattered
golden scales, showing two dark eye-
like spots; head white, dark on each
side and behind _albocephala_, Theobald.
Thorax brown with golden stripes;
abdomen with narrow basal bands on
fifth and sixth segments only _auriostriata_, Banks.
δδ. Abdominal banding indistinct.
Thorax with broad silvery white patch
on each side in front _albolateralis_, Theobald.
δδδ. Abdomen unbanded.
Thorax with six silvery spots _argenteopunctata_, Theobald.
δδδδ. Abdomen with apical white lateral spots.
Thorax unadorned, except for pale
scaled lines laterally _punctolateralis_, Theobald.
δδδδδ. Abdomen with basal white lateral spots.
Thorax with two pale median parallel
lines and two silvery lateral spots _ininuta_, Theobald.
Thorax unadorned.
A white spot middle of head _tripunctata_, Theobald.
No white spot _amesii_, Ludlow.
AAA. Proboscis yellow basally, dark
apically. Abdomen with apical pale
bands _crassipes_, Van der Wulp.
AAAA. Proboscis with median interrupted white
line on basal half.
Head black, anterior margin grey _albomarginata_, Newstead.

*Stegomyia fasciata*, Fabricius (Yellow Fever Mosquito).

This insect, which is the proven carrier of yellow fever, is commonly
called the tiger, brindled, spotted day or striped mosquito. It
is also referred to by some writers as _S. calopus_, Meigen. It
is subject to considerable variation in colour, but the thoracic
markings are generally very constant. The general colour is almost
black to deep brown, the head with a median white area, white at
the sides and in front around the eyes; the thorax has two median
parallel yellow lines, a broad curved silvery one on each side and
white spots at the sides; the scales on the intervening spaces of the
thorax are brown. The dark abdomen has basal white bands and basal
white lateral spots. The dark legs have basal white bands, the last
segment of the hind legs being all white except in a variety from
South America and the West Indies (_luciensis_), which has the tip of
the last hind tarsal dark. The abdomen may also vary in colour, some
having pale scales over most of the surface (_queenslandensis_).

The food of the adult female consists mainly of man’s blood, but she
will also feed on dogs and other animals. The male has been said to
bite, but such is very unusual. This mosquito bites mainly in the
daytime up till about 5 p.m.

The adults breed the first day after emergence. They may live a
considerable time, Bancroft having kept females for two months in
confinement. The ova are laid separately, often in chains; they
are black, oval, with a reticulated membrane outside, some of the
reticulated cells containing air. They may hatch in from six to
twenty hours, the larval stage nine days, the pupal stage three; thus
the whole cycle may be completed in from twelve to thirteen days.
The ova when dry can remain undeveloped for a considerable time. The
larvæ are greyish-white, with short, thick siphon, and feed at the
bottom of the water, only coming to the surface now and again to
breathe. This is almost entirely a domesticated gnat, seldom being
found far from man’s habitations. Its larvæ occur in such small
collections of water as old sardine tins, jam-pots, calabashes,
puddles, barrels, wells--in fact, wherever water is held up, even to
the gutters of houses. Not only are they found breeding on land, but
also on board ship, although they prefer artificial collections of
water. They may also breed in larger natural collections.

This insect is easily transported by steam and sailing ships and by
train, and this doubtless explains its very wide distribution. The
adults may live for fifty days, and it is on this account and their
frequent occurrence on ships that danger lies in regard to the Panama
Canal. An infected insect may leave that endemic centre of yellow
fever and live until the vessel arrived at the Philippine Islands and
fly ashore, and so introduce the disease for the native _fasciata_
possibly to spread.

Roughly the distribution of this pest is as follows: Africa from
South to North, but especially along the coast and up the Nile. In
Asia, in India, Ceylon, Burma, Siam, along the ports of the Malay
Peninsula, in French Cochin China, Philippine Islands, the Andaman
and Nicobar Islands, Japan, Malay Archipelago, and East Indies,
Turkey in Asia, Arabia and Palestine.

In Australia it occurs in Queensland, New South Wales, Victoria and
South Australia.

In Europe in Italy, Spain, Portugal, Greece, in the Mediterranean
Islands.

In South America, Central America, Mexico, North America, and the
West Indies it is very abundant, and it also is found in the Bahama
Islands, Fiji, Sandwich Islands, Samoa, the Azores, Teneriffe and
Santa Cruz, Pitcairn Islands and Bermuda.

For a full account of its distribution the reader is referred to the
following: “The Distribution of the Yellow Fever Mosquito (_Stegomyia
fasciata_, Fabricius) and General Notes on its Bionomics;” “Mém.
1^{er} Congrès international d’Entomologie, 1911, ii, pp. 145–170,
F. V. Theobald.” In addition to being the yellow fever carrier, it
is supposed by Wenyon to be the intermediate host of the parasite of
Bagdad sore.

*Stegomyia scutellaris*, Walker.

A vicious biter, found in India, China, Malay, East Indies, and
Ceylon. The thorax has one median silvery stripe, and so can easily
be told from _S. fasciata_.

A very similar species occurs in Fiji, but can be told by the pleuræ
having white lines, not spots (_S. pseudoscutellaris_, Theobald). It
is the intermediate host of filaria in Fiji (Bahr).

A number of nearly allied genera occur here (_vide_ synoptic table).

Genus. *Theobaldia*, Neveu-Lemaire.

*Theobaldinella*, Blanchard.

Includes several large Culicines, of which _T. annulata_, Meigen,
is the type. The wings are usually spotted (_annulata_, _incidens_,
etc.), but may be nearly plain (_spathipalpis_). The males have the
palpi swollen apically, and the females have long five-jointed palps.

Several of these are vicious biters.

*Theobaldia annulata*, Meigen.

This large gnat (6 mm. long) can be told by its wings having five
large spots of dark scales and by its legs having broad basal white
bands to the tarsi. The larvæ occur in rain barrels and small pools.
It is essentially a domestic form, occurring in houses and privies.
Its distribution is Europe generally and North America. The bite is
very severe, and in some districts gives rise to painful œdema.[392]

[392] Theobald, “Second Report on Economic Zoology,” 1903, p. 9.

_Theobaldia spathipalpis_, Rondani, occurs in Italy, Mediterranean
Islands, Palestine, the Himalayas, Khartoum, and in South Africa. It
is about the same size as _T. annulata_, but is yellowish-brown in
colour, with striped thorax and mottled and banded legs. It occurs in
privies and bites very severely.

Genus. *Culex*, Linnæus.

“Syst. Nat. Ed.,” 1758, x, Linnæus; “Mono. Culicid.,” 1901, i,
p. 326; 1910, v, p. 322, Theobald.

This large genus still contains many forms which should be excluded.
The species normally have narrow curved median head-scales, and
similar ones on the scutellum; the female palpi are shorter than
in the former genus and the male palpi are pointed; the lateral
vein-scales are narrow and linear.

The type is _Culex pipiens_, Linn., the common gnat of Europe.
The thorax is covered with narrow curved golden-brown scales,
the abdomen has basal pale bands to the segments and the legs and
proboscis are unbanded. The stem of the first submarginal cell is
always less than one-fifth the length of the cell. It lays its eggs
in rafts in water-butts, etc., and even in the foulest water. They
are first deposited in England in June and July, and again soon after
hatching in August. In some districts this gnat bites man viciously,
in others not at all.

The common tropical gnat (_Culex fatigans_, Wied). This resembles the
European _Culex pipiens_, but can always be told by the stem of the
first submarginal cell always being much longer than it is in _C.
pipiens_. This is one of the species that has been proved to transmit
filariæ to man, etc. Varieties of it occur in almost every country
between 40° N. and S., having a very similar range to _S. fasciata_.
In all countries it appears to be connected with the transmission of
_Filaria bancrofti_, and it is also said to carry the micrococcus of
dengue fever.

Genus. *Melanoconion*, Theobald.

“Mono. Culicid.,” 1903, iii, p. 238; 1907, iv, p. 507; 1910, v,
p. 455.

This genus is composed of eight species, most of which are small
black gnats which bite viciously and which occur in swamps and
jungles. They can at once be told from Culex by the veins of the
wings having dense broadened scales on their apical areas and along
the upper costal border. The femora and apices of the tibiæ are
swollen.

The black mosquito, _Melanoconion atratus_, Theob. This small
gnat is a very troublesome pest in swamps in the West Indies. The
female bites both by day and by night, and the bite causes severe
irritation. The larvæ live in permanent ponds. It is almost black in
colour, but sometimes presents a dull coppery sheen; each segment has
small lateral basal white spots. Length 2·5 to 3 mm.

It occurs in Para and British Guiana as well as in the West Indies.

Ordinary mosquito netting is no use for keeping off this pest.

Genus. *Grabhamia*, Theobald.

“Mono. Culicid.,” 1903, iii, p. 243; 1907, iv, p. 284; and 1910, v,
p. 277.

Allied to Culex, but separated by the wings having short fork-cells,
mottled scales, the median ones thick and also some of the lateral
ones short and broad; the last two joints of the male palps are very
slightly swollen. The eggs are laid singly, not in rafts, and the
larvæ have short, thick siphons. Ten species occur and are found in
Europe, North America, West Indies and Natal. _G. dorsalis_, Meigen,
bites severely in Europe. _G. sollicitans_, Walker, is a great
scourge along the New Jersey Coast and at Virginia summer resorts
and in Florida. It breeds in brackish water and is the most common
mosquito of the Atlantic seaboard.

Genus. *Pseudotæniorhynchus*, Theobald; *Tæniorhynchus*, Theobald, non-Arribalzaga.

Differs from the former in having the whole wing veins clothed with
dense, broadish elongated scales. They occur in South America (_T.
fasciolatus_, Arri.), in Africa (_T. tenax_, Theob.), in Europe (_T.
richardii_, Ficalbi). The latter bites very severely.

Genus. *Tæniorhynchus*, Arribalzaga; *Mansonia*, Blanchard; *Panoplites*, Theobald.

_Compt. rend. heb. Soc. Biol._, 1901, iii, 37, p. 1046; “Mono.
Culicid.,” 1901, ii, p. 173; and 1910, v, p. 446, Theobald.

A very marked genus, easily told by the broad asymmetrical wing
scales. It occurs in Africa (_T. africana_ and _T. major_, Theob.);
in Asia (_T. uniformis_, Theob.; _T. annulipes_, Walker, etc.) and in
Australia (_T. australiensis_); in the Americas and West Indies (_T.
titillans_, Walker). The eggs (fig. 395, _d_) are peculiar in form
and are laid separately; the larva has not been described; the pupa
has long curved siphons. They mostly occur along rivers, in swamps
and forests, and bite very severely. They also enter houses (_T.
titillans_). _T. uniformis_ is most troublesome during the rains.
The saliva is strongly acid. Both these species carry the larvæ of
_Filaria bancrofti_.

Genus. *Chrysoconops*, Goeldi.

“Os Mosq. no Para,” 1905, p. 114, Goeldi; “Mono. Culicid.,” 1910, v,
p. 433, Theobald.

Bright yellow or yellow and purple mosquitoes, with rather dense wing
scales. Numerous species occur in Africa (_aurites_, _annettii_,
_fuscopennatus_, etc.), others in India, Australia and South America.

Low found filariæ in the thoracic muscles of _fuscopennatus_ in
Uganda.

Several of the _Ædeomyina_ bite, especially the small _Uranotænias_.
They are all sylvan species, seldom entering houses. They need not,
therefore, be referred to here.

For full details of the Culicid genera and species the reader is
referred to my monograph[393] and other works mentioned below.

[393] “A Monograph of the _Culicidæ_ of the World,” 5 vols. and atlas, 1901 to 1910, British Museum (Nat. Hist.); and the following: Howard, Dyar and Knab, “The Mosquitoes of North and Central America and the West Indies,” 1912; James and Liston, “The Anophelinæ of India,” Leicester, 1908; “The _Culicidæ_ of Malay,” Inst. Med. Res., Fed. Malay States, iii; _Ann.Trop. Med. and Par._, papers by Newstead and Carter; _Mem. Inst. Oswaldo Cruz_, papers by Lutz, Neva, Chagas; and the _Bulletin of Entomological Research_, etc.

Other Nematocera.

Other nematocerous flies are midges, daddy-long-legs and sand-flies.
The ones which cause annoyance to man besides _Culicidæ_ are the
following:--

Sand-flies (_Simulidæ_), certain midges (_Chironomidæ_), and a few
owl midges (_Psychodidæ_).

The _Nematocera_ have long thread-like jointed antennæ and their pupæ
are, as a rule, naked; the larvæ have a distinct head and can thus be
told from the next section (_Brachycera_).

Family. *Simulidæ.*

This family consists of a single genus, Simulium, Latreille, which
Roubaud has recently divided into two sub-genera called Pro-Simulium
and Eu-Simulium. These insects, which are frequently spoken of as
sand-flies, are found in all parts of the world; they are all small
insects varying from 1·5 to 3 mm. The females are very bloodthirsty,
but the males appear to be incapable of sucking blood.

The head sunk under the humped thorax; antennæ short, straight;
palpi short and broad, of four segments, bent; wings broad and in
some iridescent, legs stout. The male has holoptic eyes, whilst in
the female they are small and widely separate. The sucking proboscis
is short. The thorax and abdomen are clothed with short hairs which
may form spots and markings; these are golden, silvery, grey, or
brownish. In the sub-genus Pro-Simulium the second segment of the
hind tarsi in both sexes is elongate, linear, and without a basal
notch; in Eu-Simulium it is short, curved, and dorsally notched at
the base.

_Simulidæ_ often occur in swarms, and attack not only man but cattle,
horses, and poultry. In some districts they are more annoying than
mosquitoes.

Their life-cycle has been most completely worked out by King, in
Africa.

The larvæ and pupæ occur in swiftly flowing water, by waterfalls, in
rapids, etc. The ova are laid in gelatinous masses on plants or rocks
close to or overhanging the water. The larva is cylindrical, enlarged
posteriorly, where it is provided with a sucker, by means of which it
attaches itself to a rock, water weeds, debris, etc.; anteriorly it
has a proleg close behind the head on the lower surface. The head is
dark and chitinous. The respiration takes place by means of branched
tracheal gills which protrude from the dorsal surface of the last
body segment; they are retractile. The colour varies from deep green
to yellow or almost black. Their food consists of algæ and other
organisms in the water brought to their mouth by two fan-like organs
placed on the head. The larvæ can crawl from place to place by means
of the thoracic proleg; they occur in masses, usually in a more or
less erect attitude. A network of threads is spun on their support,
by means of which King tells us “they are enabled to maintain their
position against the strongest current; frequently they will leave
their support and let themselves out into the stream anchored by
threads of silk and enabled by them to return.”

When full fed the larva spins a pocket-shaped cocoon on the support,
within which it pupates. The pupa is motionless and has a pair of
branched spiracles projecting from behind the head. When the adult
emerges, a bubble of air collects around it, and in this it floats to
the surface and at once takes wing. The European species take a month
to complete larval life, a week being spent in the pupal stage. The
flies are most restless, and even when stationary continually move
their legs about like feelers. Sometimes the swarms consist entirely
of females, sometimes early in the season mostly of males.

The females pierce the skin of humans on tender spots, such as ears,
the forehead, around the eyes and nose, and crawl into the cavities.
They are quite harmless at night, mainly attacking about sunrise and
sunset. Some crawl up the arms and legs and down the neck, and leave
behind little red weals which itch intensely (_S. damnosum_, Theob.),
and blood may flow freely from the wounds.

The following are some of the worst species:--

_Simulium columbaschensis_, the “Kolumbatz fly,” which abounds in the
damp marshy lands along the Danube, and is a great plague to man and
beasts in Hungary, and is also abundant in Austria and Moravia, and
is most numerous after inundations from the Danube. They sometimes
appear in such swarms that it is impossible to breathe without
getting them into one’s mouth. There are instances of children being
killed by these flies when left on the ground by their mothers when
working in the fields.

_S. damnosum_, Theob. This occurs throughout Equatorial Africa and is
known as the “jinja fly” in Uganda, the “fouron” in the French Congo,
the “kilteb” in the Sudan. It is a most vicious biter, and in some
parts occurs in “belts”; Dr. Christy found one such extending from
the shores of the Victoria Nyanza northwards along the right bank of
the Nile for twelve or fifteen miles or more, and perhaps three or
four miles wide. In this area the flies swarm in millions at certain
seasons, so much so that the natives have to leave their plantations.
The bite causes a weal, marked by a drop of blood.

_S. griseicollis_, Becker. The so-called “nimitti” occurs in Upper
Egypt and the Anglo-Egyptian Sudan. It lives near the river and is
not found more than half a mile from it. Human beings are bitten on
the face and hands, animals in the region of the pudenda.

_S. latipes_, Meigen. This is a European species, also found in Natal.

_S. wellmanni_, Roubaud. The “ohomono” of Angola, where it bites
viciously and is dreaded by the naked porters.

_S. buissoni_, Roubaud. Occurs in abundance in the Marquesas Islands.
It has been _suggested_ that this species may help to propagate
leprosy.[394]

[394] _Bull. du Mus. d’Hist. nat._, 1906, xii, p. 522.

A large number of these insects have been described by Lutz in
Brazil.[395]

[395] _Mem. Inst. Oswaldo Cruz_, 1910, ii, fasc. 2, pp. 211–267.

A _Simulium_ sp. (?) is very harmful to poultry in Cape Colony.[396]

[396] C. Fuller, “A New Poultry Pest,” 1899, Leaflet No. 1, Dept. Agric.

In America, _Simulidæ_ are most annoying. One, _S. meridionale_,
Riley, also known as the turkey gnat in the Mississippi Valley, has
been supposed to be the carrier of chicken cholera; anyhow, it has
caused the death of thousands of chickens and turkeys in Virginia
annually.[397]

[397] _Insect Life_, 1888, i, p. 14.

In Mexico Townsend found a Simulium which was named _S.
occidentalis_, which caused great annoyance to man, many people being
so susceptible to them as to preserve through the gnat season a
chronic inflammation of the exposed parts of face and neck, resulting
from the repeated bites giving rise to sores.[398]

[398] _Ibid._, 1893, v, p. 61.

Men and horses have been partially incapacitated by the bites of
sand-flies or Simulium in a Hampshire wood (Cantlie, _Brit. Med.
Journ._, April 28, 1900, v, No. 2,052, p. 1023).

Family. *Chironomidæ* (Midges).

The _Chironomidæ_ or midges are not only frequently mistaken for
mosquitoes, but some are very annoying to man by biting him as
mosquitoes do. They are easily distinguished from true mosquitoes
(_Culicidæ_) by the following characters: (1) head small, often
retracted under the cowl-like thorax; (2) no scales to the wings
or body; and (3) the different arrangement of veins on the wings
(fig. 402).

Two genera are important as annoying man, namely, Culicoides,
Latreille, and Johannseniella, Williston. The larvæ of _Chironomidæ_
are either aquatic, both fresh water and marine, and help to
make the former foul,[399] according to Slater, or may, as in
_Ceratopogoninæ_, live beneath the bark of trees, etc. The pupæ
are very varied and also the life-histories of the different
genera.[400] The blood-sucking habit is confined to the sub-family
_Ceratopogoninæ_.

[399] _Entomologist_, 1879, p. 89.

[400] Theobald, “An Account of British Flies,” i, p. 172.

Sub-family. *Ceratopogoninæ.*

This sub-family of midges consists of very small species varying from
1 to 2 mm. in length; the wings have darkened areas, and the second
longitudinal vein is wanting, and the first and third veins are
stouter than the others and placed close to the anterior margin, the
fourth and fifth are forked; the antennæ in both male and female are
composed of fourteen segments, six or eight in the males bearing long
hairs.

The chief blood-sucking species belong to the genera Culicoides,
Latreille, and Johannseniella, Williston. The latter genus differs
from the former in the absence of an empodium or median appendage on
the last segment of the tarsi. The genus Ceratopogon, as restricted
by Kieffer, is not supposed to take vertebrate blood, but Austen has
recently noticed that the type specimen of _C. castaneus_, Walker,
and a new species described by him, apparently have their bodies
distended with blood. The wings in the _Ceratopogoninæ_ are carried
flat when at rest.

In spite of their small size the females are the most bloodthirsty
and annoying of all insects. The Culicoides, which are often called
“sand-flies,” bite during the day and rarely at night. Usually they
are most troublesome between 3 and 6 p.m. They frequently attack in
swarms, especially in the open, and owing to their minute size can
get through fine mosquito netting. Some of them produce a distinct
“buzz” when on the wing. These insects are found in all parts of the
world. No species has been definitely connected with any disease, but
Culicoides has been suspected of carrying the germs of Delhi boil.
The larvæ of Culicoides are elongate in form and have smooth bodies
composed of thirteen segments including the head, which is horny;
there is no proleg on the first segment as seen in Chironomus, and on
the anal segment are retractile gills. They are very active and live
in the sap of various trees which saturates diseased bark.

The pupæ are smooth, but the abdominal segments bear a transverse
row of small spines. Austen describes a number of Culicoides and one
Johannseniella and three Ceratopogons from Africa,[401] and Lutz[402]
a number of this sub-family from Brazil, including a new genus,
Centrorhyncus. Another genus, Tersesthes, Townsend (Centrotypus,
Grassi; Mycterotypus, Noe), also occurs in Brazil.

[401] _Bull. Ent. Res._, 1912, iii, pp. 99–108.

[402] _Mem. Inst. Oswaldo Cruz_, 1913, v, fasc. 1, pp. 45–72, pls. 6–8; and 1914, vi, fasc. 2, pp. 81–99.

_Culicoides ornatus_, Taylor, is described from Townsville,
Australia, found in mangrove swamps. It is a very vicious biter and
causes considerable irritation, settling on hands and wrists (Taylor,
_Rep. Ent. Aust. Inst. Trop. Med._ (1912), 1913, p. 24).

Family. *Psychodidæ* (Owl Midges).

This family of diptera is of considerable importance, not only on
account of the blood-sucking habits of some species, but especially
on account of one at least having been proved to be the carrying
agent of “papataci” fever, a three-day fever very prevalent in Malta
and several parts of Southern Europe in the autumn.

It is also possible that these small flies are connected with the
formation of “Delhi boil,” caused by a protozoan parasite.

_Psychodidæ_ are all very small flies, many of which have a moth-like
appearance, and owing to their fluffy nature are spoken of in
Britain as “owl flies,” sometimes also as “window flies.” Their
bodies and wings are covered with hairs, densely in some (sub-family
_Psychodinæ_), and in a few with patches of flat squamæ. In the
non-blood-sucking _Psychodinæ_ the wings are carried in a peculiar
manner downwards over the body, to a _slight extent_ resembling the
_Hepialidæ_, or swift moths. The wings may be ovoid or lanceolate,
and have a marked venation as seen in the figure. The proboscis
is short and non-suctorial in the majority of genera, but in the
sub-family _Phlebotominæ_ it is elongated and hard. The antennæ are
long and of sixteen segments, and bear whorls of fine hair.

There are two sub-families, _Psychodinæ_ and _Phlebotominæ_; in the
former the mouth is not suctorial; the female has a horny ovipositor
and the second longitudinal vein is branched at the root of the wing;
in the second sub-family the proboscis may be formed for sucking,
the female has no horny ovipositor, and the second long vein has its
first fork near the middle of the wing.

The sub-family _Phlebotominæ_ contains the genus Phlebotomus, which
occurs in South Europe, South Asia, Africa, North and South tropical
America. They are all small grey, brown, or dull yellow-coloured
flies, and carry their wings when at rest upwards like a butterfly.
The proboscis is moderately long and the legs long and thin.

The females are most vicious blood-suckers, but in some species
anyhow the males also bite (_P. duboscii_). They are mainly
nocturnal feeders and hide away during the day in any dark corners or
crevices.

The life-cycle has been worked out by Newstead[403] and Grassi[404]
in Europe, and by Howlett[405] in India.

[403] _Bull. Ent. Res._, 1911, ii, pt. 2, pp. 47–78.

[404] “Ricerche sui Flebotomi,” _Mem. della Soc. ital. della Scienze_, 1907, ser. 3, xiv, pp. 353–394.

[405] “Indian Sand-flies,” _Ind. Med. Cong._, 1909, sec. III, pp. 239–242.

The larvæ have been found in crevices in rocks and caves, in dirty
cellars, and dark damp places containing rubbish, and are also said
to live in crevices in the walls of privies and cesspits.

The minute larva is very marked; as figured by Newstead it has two
long chætæ projecting upwards, in some stages branched, in others
simple, and on the segments a few blunt spine-like processes. The
pupæ are found in similar situations. The ova are very minute,
elongate, translucent white, and covered with a thin coating of
viscous matter when first laid; soon after they become dark brown,
shiny, with long black wavy lines. Newstead found the incubation
period in Malta to last for about nine days in _P. papatacii_. Five
species are known in Europe, five in Africa,[406] two in North
America, and eight are described by Annandale[407] in the Oriental
region. Lutz and Neiva have described three species from Brazil[408]
(_P. longipalpis_, _intermedius_ and _squamiventris_).

[406] Newstead: _Bull. Ent. Res._, 1912, iii, pp. 361–367.

[407] _Rec. Ind. Mus._, v, pt. 3, Nos. 13 and 14.

[408] _Mem. Inst. Oswaldo Cruz_, 1912, iv, fasc. I, pp. 84–95.

*Brachycera* (Flies).

The antennæ as a rule have three segments, and are usually shorter
than the head. The first segment of the antennæ is frequently very
small, and the third one is generally the largest, and sometimes
possesses a terminal annulated bristle. The palpi have from one to
three segments; the mandibles are covered by the labium. The three
thoracic rings are coalesced; wings are almost always present, the
posterior ones being rudimentary and covered with a little scale.
From the ova legless maggots are hatched, which as a rule have not a
distinct head, but occasionally possess two claw-like hooklets. These
maggots live in decomposing organic matter; they rarely live in water
and some of them are parasitic. They either become barrel-shaped
pupæ within the last larval integument or, after casting it, are
transformed into naked pupæ. The larvæ of numerous _Brachycera_
have been observed in man, some in ulcers or on mucous membranes,
others in the skin or in the intestine, etc. In many cases the report
only mentions the presence of the larvæ of flies; in other cases
the species has been determined; whilst in still other cases the
corresponding adult creature is unknown. We must therefore confine
ourselves to describing the most common varieties.

Family. *Phoridæ.*

These flies belong to the same division of _Diptera_, the Aschiza, as
the family _Syrphidæ_ or “hover flies.” They are all small insects
with marked antennæ and wings; the former have the third segment
globular and enlarged, and thus hiding the first two; the wings are
short and broad, the venation shows two short, thick, long veins with
four thin ones running out from them. The larvæ normally live in
decaying animal and vegetable matter, but one species, _Aphiochæta
ferruginea_, Brun., has been found as an intestinal parasite of man.

*Aphiochæta ferruginea*, Brun.

This small fly belonging to this family is of an orange-ochreous
colour, the upper part of the thorax tawny, and with dark bands on
the abdomen, legs pale yellow, the hind femora tipped with dark
brown. It measures only 2 to 3 mm. in length. This insect is shown by
Austen to be widely distributed in the tropics, being found in India,
Burma, West Africa, and Central America. The larvæ breed in decaying
animal matter, such as putrid meat, decomposing shell-fish, etc.

Heusner bred out sixty-three flies from larvæ taken from an Indian’s
foot.

Baker (_Proc. Burma Branch Brit. Med. Assoc._, 1891, p. 11–16) found
that the maggots of this fly were passed _per anum_ by a European at
intervals during a period of ten months. Baker found that the larvæ
fed on human fæces; from the egg stage to the deposition of eggs from
the resultant brood of flies occupied twenty-two days. He concludes
that they are capable of propagating, and do so while living within
the human intestines. He also records the larvæ in two girls.

The larva does not seem to have been described, but Austen describes
the pupa (_Trans. Soc. Trop. Med. and Hyg._, iii, No. 5, p. 229).

*Phora rufipes*, Meig.

The larvæ of the “hump-backed fly” live in rotting potatoes,
mushrooms, radishes, etc., and when accidentally introduced into the
intestine of man can, like other larvæ, live there twenty-four hours
and even more, and may set up serious gastric disturbances.

_P. rufipes_ is the same as _P. pallipes_, Latr.

Family. *Sepsidæ.*

Small blackish flies, elongate, with abdomen narrowed at the base,
thickened and curved downwards towards the extremity. Larvæ often
found in decaying vegetables, ham, cheese, etc. The larvae have the
power of skipping; conical in form, pointed in front, truncated
behind, about 5 mm. long, shiny and smooth, the anal segment with
fleshy protuberances. The genus Piophila has a short proboscis and
the cross-veins of the wings approximate.

*Piophila casei*, L.

Cheese flies. The larvæ live in ripe cheese, with which they are
sometimes introduced into human beings (Meschede).

The larvæ of the cheese flies (_Piophila casei_) may pass through the
alimentary canal of human beings alive, and have been occasionally
referred to in cases of internal myiasis. It also breeds in dead
bodies in adipose tissue. Howard records it on human excrement. It
is thus possible that some of the recorded cases of this pest being
passed alive may be due to eggs deposited on human fæces.

Family. *Syrphidæ* (Hover and Drone Flies).

Amongst the large family of _Syrphidæ_ is found a section known as
the _Eristalinæ_ or drone flies, whose curious long-tailed larvæ
are popularly called “rat-tail larvæ,” on account of the end of the
body being drawn out into a long telescopic tail of two segments,
at the end of which are placed the breathing pores. These larvæ
live in water, no matter how foul, and in liquid manure. They have
occasionally been obtained in foul drinking water by human beings
and from eating watercress improperly washed or from badly kept
beds. Austen (_Trans. Soc. Trop. Med. and Hyg._, iii, No. 6, p. 221)
records that in the autumn of 1907 a number of the larvæ of the
common drone fly (_Eristalis tenax_) were passed _per rectum_ by a
woman in Hampshire who had recently arrived from France. The patient
had eaten a considerable quantity of watercress before leaving
France. I have twice found small Eristalis larvæ clinging by their
long tails on watercress served at table.

Family. *Drosophilidæ.*

Small, rather plump flies, with short, broad abdomen, with bristles
on the head and legs. Often abundant in decomposing fruit, and may
occur in dense masses.

*Drosophila melanogaster*, Br.

The larvæ of this fly occur in over-ripe fruit and in fungi, often
also in human habitations, and live in substances undergoing acid
fermentation (vinegar, decaying fungi, rotting fruit, in damaged
spots in diseased trees), much more rarely in animal substances, and
they occasionally gain access to the human intestine (for example, by
the medium of sour milk). When introduced in any quantity, they cause
vomiting or attacks resembling colic; when taken in the pupal stage
no unpleasant results are produced.

Family. *Muscidæ.*

*Teichomyza fusca*, Macq.

Syn.: _Scatella urinaria_, Rob. Desv.; _Ephydra longipennis_, Meigen.

The larvæ live in the urine in privies. Several authors state they
have found them in fresh fæces or in vomited matter. Pruvot states
that they continue for three days in the stomach of rats into which
they have been intentionally introduced. (Pruvot, G., “Contrib. à
l’étude des larves de dipt, trouv. dans le corps humain,” _Thèse de
Par._, 1882; Chatin, J., in _Comp. rend. Soc. de Biol._, Paris, 1888
(8), v, p. 396; Roger, H., _ibid._, 1851 (1), iii, pp. 88, etc.)

*Homalomyia canicularis*, L., etc.

_Homalomyia manicata_, Meig., live as larvæ in decomposing vegetable
matter or in cultivated vegetables (cabbage); they are easily
recognizable by their plumed bristles, which are situated laterally
on the body segments. They obtain access fairly often to the human
intestine and give rise to very uncomfortable symptoms. Cases have
been recorded from Germany, Austria, France, England, North America
(Wacker, in _Artzl. Intelligenzbl._, 1883, xxx, p. 109; Florentin,
in _Compt. rend. Soc. de Biol._, Paris, 1904, lvi, p. 525; and other
authors).

The larvæ of an allied genus (Anthomyia), which, however, does not
possess plumed bristles, has been found in the external auditory
meatus of a man (_A. pluvialis_, according to Danthon).

[_H. canicularis_ is common to Europe and North America, and is
an abundant house-fly. It is the small house-fly so often seen
on windows. Besides living on vegetable matter, they have also
been found in the nests of the humble bee. Larvæ of this species
(fig. 405) were sent to the British Museum, taken from the fæces of
a woman suffering from cancer.[409] They were found at Shrewsbury.
Hagen[410] reports the larvæ of this fly as occurring alive in the
urethra of a patient.--F. V. T.]

[409] Theobald, “First Report Economic Zoology,” _Brit. Mus. (Nat. Hist.)_, p. 55.

[410] Hagen, _Proc. Bost. Soc., N.H._, xx, p. 107.

*Homalomyia scalaris*, Fabr.

[This is not a synonym of the above, but a distinct species.

[_H. manicata_, Meigen, is also distinct.--F. V. T.]

*Anthomyia desjardensii*, Macq.

This fly, allied to Homalomyia, is the cause of both intestinal and
cutaneous myiasis at Bihé, Angola (Wellman, _Journ. Trop. Med. and
Hyg._, June, 1907, x, p. 186).

*Hydrotæa meteorica*, L.

The larvæ live in decaying vegetable substances, also in dung, and
have been evacuated in some cases by man (Zetterstedt, Joseph).

*Cyrtoneura stabulans.*

Larvæ in fungi, but occasionally also on larvæ of butterflies and
_Hymenoptera_; occasionally introduced into the human intestine
(Joseph).

*Musca domestica*, L.,

and _M._ (_Calliphora_) _vomitoria_, L., and allied species; larvæ
of these have been repeatedly found in the intestine and nose of man
(Mankiewicz, etc.).[411]

[411] “Larvæ of a Musca, probably _M. corvina_, were passed in numbers _per rectum_ by a child in Liverpool with Homalomyia larvæ,”--“Second Report Economic Zoology,” Theobald, 1903, p. 16.

*Musca domestica*, Linn. (Common House-fly).

It is not only on account of a few larvæ of the common house-fly
(_Musca domestica_) being found in the intestines of man that it is
of importance medically. It is far more important on account of the
part it plays in the spread of diseases of the intestines, such as
typhoid fever and cholera, infantile diarrhœa and dysentery.

Howard and Clark (_Journ. Exp. Med._, 1912, xvi, No. 6, pp. 850–859)
have shown that the house-fly is capable of carrying the virus of
poliomyelitis for several days on the surface of the body and for
several hours in the gastro-intestinal tract. The house-fly may also
distribute the ova of _Tænia solium_ and the white worms (Oxyuris and
Ascaris). It has also been proved that they may carry the germs of
tuberculosis, and it is said that they play an important part in the
spread of infectious ophthalmia in Egypt.

This insect is found in all parts of the world. In warm countries
it breeds all the year round, and it may do so even in temperate
climates in warm places, such as stove houses. Most, however, die
off in the autumn; but some survive the winter as adults, in such
places as kitchens, restaurants, and warm houses. I have never failed
to find a few _Musca domestica_ in houses during the winter. The
majority, however, hibernate as puparia.