Chapter XXX: Section C: Proboscis short, not formed for (2)

The females deposit from 120 to 150 eggs in a batch in stable
manure, rotting vegetation, house refuse, spent hops, old soiled
bedding, etc. A single female may lay as many as six batches of ova
during her life. The eggs are shiny white, and hatch in from eight
to twenty-four hours in warm weather to three or four days in cool
weather. The white footless maggots are cylindrical, tapering to a
point at the head end, truncated posteriorly. The head consists of
two dark mandibular hooks and two short antennæ. On the tail end are
two plates, the stigmata, in which the main tracheal trunks open;
in the second segment are a small pair of projecting stigmata. The
larval stage lasts from seven to five days in hot weather; but in
cold weather in temperate climes it may last six or eight weeks.

The larva on reaching maturity becomes a barrel-shaped puparium of
a dark brown to black colour, and in this case changes to the pupa.
This stage lasts from three days in the tropics to four or five weeks
in cold weather, the life cycle thus varying from ten days in the
tropics to fourteen in warm weather in Europe up to three or four
months under unfavourable conditions.

All breeding grounds should be burnt or otherwise done away with,
such as stable manure, house and kitchen refuse, human excrement and
soiled substances, also decaying vegetation as soon as possible,
certainly by every sixth day. Stable manure should be kept in closed
receptacles and should be removed by every sixth day to at least
one mile from habitations and sprinkled with chloride of lime. All
kitchen and household refuse should be burnt at once or buried in
pits and covered with soil. Latrines should be as far as possible
from hospitals, mess rooms and tents. Food--especially milk, sugar
and fruit--should be kept screened with muslin when house-flies
are about. Mess rooms and tents and hospitals should have doors
and windows screened with fine wire gauze during the fly season.
All possible steps should be taken to prevent them contaminating
man’s food and from breeding in human excrement and from entering
hospitals. When present in dwelling-houses in numbers they may be
killed by fumigation with pyrethrum or sulphur.

Genus. *Chrysomyia*, Rob. Desv.

*Chrysomyia* (*Compsomyia*) *macellaria*, Fabr.; *Lucilia macellaria*, Fabr.

Syn.: _Lucilia hominivorax_, Coq.; _Calliphora infesta_, Phil.;
_Calliphora anthropophaga_, Conil.

A species distributed from the Argentine to the south of the United
States which deposits its ova on ulcers, in the aural meatus or in
the nasal cavities of persons who sleep in the open air. The larvæ
are yellowish white, 16 mm. long, are armed with two strong mouth
hooks, and provided with spinous rings (screw-worm); they lie hid in
the nasal and frontal sinuses, in the pharynx, larynx, etc.; they
perforate the mucous membranes, even cartilage, migrate into the
eyes, the cranial cavity, middle ear, and cause severe disturbances;
after the mature stage, in which the larvæ leave the host to enter
the pupal state, these symptoms often spontaneously abate after a
lapse of eight days, leaving behind greater or less cicatrices, and
consequently also defects in function of the organs attacked. Very
often, however, sepsis sets in, usually with a fatal termination.

(Coquerel in: _Arch. gén. de méd._, 1858 (5), p. 513; 1859, xiii,
p. 685; _Ann. Soc. ent. France_, 1858 (3), vi, p. 171; 1859, vii,
p. 234. Weber in: _Rec. de mém. de méd. milit._, 1867 (3), xviii,
p. 159. Francius, A., in: _Arch. f. path. Anat._, 1868, xliii, p. 98.
Conil in: _Bol. Acad. nac. cienc. Cordoba_, 1881, iii, p. 296.
Humbert, Fr., in: _Proc. U.S. Nat. Mus._, 1883, vi, p. 103; _Amer.
Nat._, 1884, xviii, p. 540. Lindsay in: _Journ. Trop. Med._, 1902; v,
p. 220, and other authors.)

[This species is known as the screw-worm fly. It attacks animals as
well as man, especially laying its eggs on wounds formed by barbed
wire. It may also be found on dead flesh. Dr. St. George Gray sent
me specimens from St. Lucia, from the nose and mouth of a patient
in Victoria Hospital. Others were found in the vagina of another
patient. Out of the four patients attacked, two occupied the same
bed, one after the other, and a third the next bed to it. The other
case was in a more remote part of the hospital. There are numerous
records of this fly attacking man. It occurs from the Argentine to
Texas.--F. V. T.]

*Chrysomyia viridula*, Rob. Desv.

[This species is somewhat larger than the former; the body is
metallic bluish-green, the dorsum of the thorax with three blackish,
longitudinal stripes, and the face ochraceous; about 10 mm. long.
Austen records this species from man, Dr. Daniels having bred it from
larvæ from a sore on a human being in New Amsterdam, British Guiana.
Dr. Laurence also bred it in Trinidad. In the latter case between 100
and 150 maggots were discharged from the nose of a woman suffering
from facial myiasis (_Brit. Med. Journ._, January 9, 1909, p. 88 +
fig.).--F. V. T.]

Genus. *Lucilia*, Rob. Desv.

*Lucilia nobilis*, Meig.

The larvæ were observed by Meinert in Copenhagen in the auditory
meatus of a person who, after taking a bath, fell asleep in the open
air, and on waking felt singing in the ears, and had a sensation
as if there were water in the auditory canal. During the next days
severe pains set in, and there was a discharge of blood and pus from
both ears, as well as from the nose. On washing out the meatus the
maggots made their appearance.

_Lucilia cæsar_ and _L. sericata_ have also been observed in the
larval state in man (Thompson, Hope, Henneberg and Calendoli, Napoli,
1907).

[This golden-green fly usually lays its eggs on decomposing organic
matter; now and again it lays its eggs in wounds on man.--F. V. T.]

Genus. *Pycnosoma*, Brauer and v. Bergenstamm.

The species of this genus have a general resemblance to the Lucilias
and Chrysomyias, but the body is stouter and the abdomen banded.
The genus can be distinguished from Chrysomyia by the absence of
the three thoracic stripes and by the eyes of the male, in which
the facets forming the upper portion are much enlarged, whereas
in Chrysomyia they are not noticeably larger. Austen also points
out that the sterno-pleural bristles in Pycnosoma are 1 : 1, in
Chrysomyia 2 : 1. The genus is found in tropical Asia and Africa
only. All records of Chrysomyia (Compsomyia) in India must be
referred to this genus. Bezzi and Stein (“Katalog der Palăarktischen
Dipteren,” 1907, iii, p. 543), however, regard the two as synonymous.

The larvæ are frequently found in the nostrils of man and burrow into
the sinus, but normally they live on decaying animal matter.

Pycnosoma forms the so-called Indian screw-worm. Patterson (_Ind.
Med. Gaz._, October, 1909, xliv, No. 10) records the case of a woman
at Tezpin, Assam, from whom as many as 100 larvæ were removed at
one time, and later the left orbital cavity was found packed with
hundreds of maggots; eventually the patient died. It is possible that
this, however, was due to a species of Sarcophaga. Austen undoubtedly
records this genus causing nasal myiasis in India (_Trans. Soc. Trop.
Med. and Hyg._, iii, p. 235). At Dehra Doon, U.P., a woman discharged
100 larvæ from her nose, with great pain in the nasal region and
frontal sinuses.

The so-called “peenash,” a common malady in Rajputana, is a true
nasal myiasis.

Genus. *Sarcophaga*, Mg.

*Sarcophaga carnosa*, L., 1758.

Larvæ of flesh-flies provided with two claws at the anterior end,
which settle on raw or cooked meat, and in the open on carcases
of animals; they are often observed in man, both in the intestine
(introduced with food) and in the nasal cavities, frontal sinus,
conjunctiva, aural meatus, anus, vulva, vagina, prepuce, and open
ulcers, often migrating further from the regions first attacked.
(Gayot in _Compt. rend. Acad. Sci._, Paris, 1838, vii, p. 125. Grube
in _Arch. f. Naturg._, 1853, xix, 1, p. 282. Legrand du Saulle in
_Compt. rend. Acad. Sci._, Paris, 1857, xlv, p. 600, and other
authors.)

[This fly is viviparous. The fly varies from 10 to 30 mm. in length,
and is of a general ash-grey colour; the thorax with three dark
stripes, the abdomen light grey with three black spots on each
segment; legs black; base of wings yellow. It also attacks animals
and birds, especially geese. The genus Sarcophaga is universally
distributed. The maggots are whitish or yellowish footless larvæ of
twelve segments, tapering to a point in front, broadened posteriorly.
There are two mouth hooks, by means of which they rasp their food.
The breathing pores are at the end and consist of two groups of three
slits, each surrounded by a hardened area. They pupate in their old
skin, which turns brown.--F. V. T.]

*Sarcophaga magnifica*, Schiner, 1862.[412]

Syn.: _Sarcophaga wohlfahrti_, Portschinsky, 1875.

[412] [The correct name for this fly is _Wohlfahrtia magnifica_, Schiner.--F. V. T.]

A species widely distributed over the whole of Europe, occurring
especially in Russia (Mohilew); the presence of the larvæ in man was
first observed by Wohlfahrt (1768). The larvæ settle in the pharynx,
in the nose, the aural meatus, the conjunctiva, and in other regions
of the human body; they also attack domestic animals and birds. As
Portschinsky has shown, they cause severe inflammations, hæmorrhages
and suppurations in the organs in which they occur; children are
especially attacked. A number of cases have been observed also in
Central and Western Europe. [The fly has a light grey abdomen with
shiny black spots which do not change their shape and appearance
according to the angle in which the fly is viewed.--F. V. T.]

(Wohlfahrt: “Observ. de vermibus per nares excretis,” Halæ, 1768;
_Nov. Act. Acad. Caes. Nat. curios._, 1770, iv, p. 277. Gerstäcker
in: _Sitzungsb. Ges. nat. Frde. Berl._, 1875, p. 108. Portschinsky
in: _Horæ soc. entom. ross._, 1875, 1884, p. 123. Laboulbène in:
_Ann. Soc. ent. France_, 1883 (6), iii; _Bull._, p. xcii. Leon in:
_Bull. Soc. des Méd. et Nat. de Jassy_, 1905, xix, p. i. Freund, L.,
in: _Verh. Ges. deutsch. Naturf. u. Ärzte_, Homburg (1902), 1902,
ii, 2, p. 450, and other authors.) [Probably most cases of attack in
Europe are due to this species.--F. V. T.]

The above cited do not exhaust the number of observations of
diptera larvæ parasitic in man; there are yet to be mentioned the
larvæ of _S. hæmorrhoidalis_, _S. hæmatodes_ (of G. Joseph), those
of _S. ruficornis_ (excitants of a cutaneous myiasis in the East
Indies), those of species of Eristalis (of Hanby and others), and
those of _Phora rufipes_ (of Kahl, of Warsaw, and others). In many
cases the determination of the diptera larvæ has been omitted
(or must be omitted); such is the case with diptera larvæ in the
eye (Schultz-Zehden in: _Berl. klin. Wochenschr._, 1906, p. 286.
Ollendorf in: _Med. Korrespondenzbl. d. würt. ärtzl. Landesver._,
1904, p. 1017. Kayser in: _Klin. Monatsbl. f. Augenheilkunde_,
1905, xliii, i, p. 205. Ewetzky and v. Kennel in: _Zeitschr. f.
Augenheilkunde_, 1904, xii, p. 337, and other cases). Austen records
several cases of myiasis due to Sarcophaga (_vide Trans. Soc. Trop.
Med. and Hyg._, 1910, iii, No. 6).

The larvæ of African _Muscidæ_ have now become of greater interest; like several Oestrid larvæ they live normally in the skin of mammals, but also attack man. The knowledge of these species is certainly very insufficient, but this is not likely to be the case much longer, as medical men practising in the Colonies are giving their attention to these parasites. At the present time four distinct forms are recognized according to Gedoelst.[413]

[413] [The following are known to cause myiasis in man in Africa: _Cordylobia anthropophaga_, Grünb.; _Auchmeromyia luteola_, Fabr.; _A. rodhani_, Gedoelst; _Oestrus ovis_, Linn.; and _Anthomyia desjardensii_, Macq. The _anthropophaga_, Blanchard, and the _depressa_, Walker, referred to here are Grünberg’s _anthropophaga_.--F. V. T.]

*Sarcophaga chrysotoma*, Wied.

[This species is recorded as attacking human beings at New Amsterdam,
British Guiana. The fly is 15 mm. long, has a golden-coloured
face, three broad black thoracic stripes and ochraceous buff anal
segments. It was bred from larvæ obtained by Dr. Roland from a sore
on a girl’s foot. It is known to occur in the Brazils and the West
Indies. Another species was also bred which Austen was unable to
identify.--F. V. T.]

*Sarcophaga plinthopyga*, Wied.

[This and other species of Sarcophaga are called “yaw flies” in
Dominica, as they are believed to be concerned in the dissemination
of frambœsia or yaws (Nicholls) (_vide_ Austen, _Trans. Soc. Trop.
Med. and Hyg._, 1910, iii, p. 239).--F. V. T.]

*Ochromyia anthropophaga*, E. Blanch.; *Cordylobia arthrophaga*, Grünberg.

Indigenous to the Senegal and neighbouring districts; in the district
of Cayor (between the mouth of the Senegal and Cape Verde) the larva
is known as the “ver de Cayor.” It lives under the skin, especially
at the lower extremities and the lower region of the trunk, producing
small boils, which cause pain, but after about eight days, when
the larva leaves the body to enter the pupal stage, the pain
discontinues. Besides man the larva occurs in dogs, goats, cats, and
in the jackal. It is still questionable whether the fly deposits its
eggs direct or on the ground, from whence the larvæ as they emerge
gain access to animals and man. Larvæ yellowish-white, 14 mm. long,
4 mm. wide, eleven segments[414]; head with two globular antennæ-like
appendages, two black curved mouth hooks, and two wart-shaped, finely
spinous structures at their base. Body evenly covered to the seventh
segment with small black prickles, which are stronger at the sides
and the anterior borders of the segments; from the seventh they
increase in size, on the two hindermost they are wanting; on the last
segment two deep yellow spiracles, each with three markedly curved
fissures; in addition two stigmata on the posterior border of the
first segment. Duration of the larval stage about eight days. Upon
the construction of roads in Guinea the larva is spread by dogs far
into the interior.

[414] [Austen gives the length as 12 to 12·5 mm. and the breadth as 5 mm.; he describes the larva as follows: Bluntly pointed at the anterior extremity, and truncate behind; from third to eleventh segments thickly covered with minute recurved spines of brownish chitin, usually arranged in transverse series of groups of two or more, which can be seen to form more or less distinct undulating and irregular transverse rows. In each of the two posterior stigmatic plates, the respiratory slit on either side of the median one is characteristically curved, resembling an inverted note of interrogation. The barrel-shaped puparium is on an average 10·3 by 4·6 mm.; its colour varies from ferruginous to nearly black.--F. V. T.]

*Auchmeromyia* (*Bengalia*) *depressa* (Walker).[415]

[415] [According to Austen this is _Cordylobia anthropophaga_, Grünb. _Bengalia depressa_, Walker, is a very different insect, whose life-history is unknown.--F. V. T.]

Distributed in the region of Natal and apparently over the whole of
South Africa. The “larva of Natal,” as one may still term the species
provisionally, as its identity is not certain, possesses on its head
(besides the mouth hooks) lateral protuberances beset with a row of
chitinous spines. The cuticle of the body is spinose. The spines are
difficult to recognize on account of their transparency and want of
colour; they are longest over the anterior segments, from the fifth
they become smaller, and over the hindermost they are very small.
Apart from the foremost segment, the position they take is that of
rows running transversely or obliquely, two to four generally in
juxtaposition; the number of spines in the groups gradually increases
posteriorly, attaining the number of eight to twelve on the sixth
segment, and this number is maintained to the end of the body.
Isolated spines are found over the head; over the second, third and
fourth segments single ones are still found adjoining the groups
of spines, from the fifth onward they are wanting. From here the
spines cover the whole free surface of the segments; over the fourth
the anterior three-quarters, over the third two-thirds and over the
first and second only the anterior half. The stigmata found at the
anterior end also serve as distinguishing characters. The parasitic
stage appears to last about fourteen days. [Fuller (_Agric. Journ._,
Dept. Agric. and Mines, Natal, 1901, iv, p. 606) refers to this as
_Bengalia depressa_ also.--F. V. T.]

Genus. *Cordylobia*, Grünberg, 1903.

*Cordylobia grünbergi*, Dönitz.

Syn.: _Ochromyia anthropophaga_, Grünberg, _nec_ Blanch.; _Cordylobia
anthropophaga_, Grünberg.

Endemic in German East Africa and neighbouring regions. Larva up
to 14 mm. long, 4 to 5·5 mm. wide, of cylindrical shape, slightly
narrowed behind, truncated, gradually tapering in front; antennæ-like
processes, cone-shaped, blunt. Smaller cylindrical formations at the
base of the mouth hooks surrounded by a circle of chitinous hooks.
Body from the first segment covered with small brown squamous spines
which are disposed in numerous irregular transverse rows. The spines
are small over the two first segments, the two posterior thirds of
all the segments, as well as from the eighth; over the third to the
seventh they are larger, but between these there are very small
spines. The breathing pores of the stigmata at the anterior end are
kidney-shaped; the orifices are elongated and very tortuous, each
divided into three. The larval period appears to last several weeks.

*Cordylobia anthropophaga*, Grünberg.

This well-known cutaneous African parasite seems to have been the
cause of much confusion in regard to names. It belongs to the genus
Cordylobia of Grünberg, and is one of the family _Muscidæ_, and
differs from Auchmeromyia in that the second abdominal segment of
the female is of normal size, whilst in Auchmeromyia it is more than
half the length of the whole abdomen, and in the male the eyes are
holoptic or close together, whilst in Auchmeromyia they are wide
apart. The flies of this genus (three so far described) attack man in
their larval stage (anyway two of the three), and also dogs and other
animals, by burrowing into the skin and producing painful boils.

[_C. anthropophaga_, Grünberg, is widely distributed in Africa,
extending from Senegal, where its maggot is known as the “ver de
Cayor,” and is referred to on p. 590 as _Ochromyia anthropophaga_,
E. Blanchard, to Natal, where it is known as the “Natal worm,” and
referred to erroneously on p. 591 as _Bengalia depressa_, Walker.

[It is a thick-set Muscid of a general straw-yellow colour, with
blackish markings on the dorsum of both thorax and abdomen, about
9·5 mm. long. The larva is fat and when mature about 12 mm. long,
bluntly pointed in front, truncate behind; from the third to eleventh
segments it is thickly covered with minute recurved spines of a
brownish colour, arranged in transverse series of groups of two or
more, which form more or less distinct irregular transverse rows.
On each of the two posterior stigmatic plates, the respiratory slit
on either side of the median one is characteristically curved,
resembling an inverted note of interrogation. The puparium is brown
to ferruginous or black and about 10 mm. long. The maggots are
found in both natives and white men, and occur as a severe pest in
dogs, also in monkeys, rats, and other mammals. In Sierra Leone it
is called the “tumba fly.” The larvæ have been frequently found as
true subcutaneous parasites, each larva living singly and forming a
boil or warble in the skin, with an opening just as in an ox-warble,
through which the maggot breathes and eventually escapes. Although
they more usually occur as isolated specimens, Marshall found in
Salisbury, South Rhodesia, that sixty were extracted from one lady,
and Bérenger-Féraud, in Senegal, that more than 300 occurred in a
single spaniel puppy.

[Neave (_Bull. Ent. Res._, 1912, iii, p. 217) records it from ulcers
in a native at Lourenço Marques in 1908, and at the same time from
ulcers in a dog, and that it is a severe pest to man in Mozambique
and parts of the Transvaal. It seems to be more abundant in North
Rhodesia and Nyasaland than to the north (Neave, _Bull. Ent. Res._,
1912, iii, p. 310). It is also recorded in Zanzibar, German East
Africa, Uganda, East Tropical Africa (Neave).

[Simpson (_Bull. Ent. Res._, iii, p. 170) records a Muscid larva
taken from the breast of a European in South Nigeria that was
probably Cordylobia.

[It is not known how infection takes place. Neave (_Bull. Ent. Res._,
iii, p. 310) says: “Many instances in human beings would preclude
the possibility of eggs having been laid direct on the skin: in these
cases they have probably been laid on the clothing put out to dry.”

[Gedoelst has described another species, _C. rodhani_, and Austen
a third species, _C. prægrandis_, from Nyasaland, Cape Colony,
Transvaal, Natal, North-west Rhodesia, and German East Africa.

[The following are some papers dealing with this subject: _Proc. Ent.
Soc._, London, for year 1907, p. xlvii; _Journ. R.A.M.C._, 1908,
pp. 5–11, figs. 1 and 2, by Austen; _Journ. R.A.M.C._, 1908, pp. 1
and 2, by Major F. Smith; _Trans. Soc. Trop. Med. and Hyg._, 1910,
iii, pp. 223–225, by Austen.--F. V. T.]

*Lund’s Larva.*

Endemic in the region of the Congo State; called after Commander
Lund, from the skin of whose arm it was extracted; 12·5 mm. long,
4·5 mm. broad; colour yellowish, with brown rings, on account
of the division of the brown spines; head cone-shaped, with
two hemispherical smooth antennæ, two thick black mouth hooks
and wart-shaped bodies, between which are situate two to three
longitudinal rows of dark brown chitinous laminæ. The body segments
are covered over their whole surface with irregularly distributed
triangular yellow spines, the points of which are coloured dark
brown. Its size increases from the second to the sixth segment,
diminishes from the seventh to the ninth, at the tenth it is
reduced, and at the eleventh quite small. The posterior stigmata are
bean-shaped, each with three markedly tortuous openings. Duration of
the larval stage unknown; the same applies to the pupal and imago
stages.

*Auchmeromyia luteola*, Fabricius.

[This fly, the parent of the so-called Congo floor maggot,[416]
belongs to a nearly allied Muscid genus to Cordylobia, but which
can at once be told by the great length of the second abdominal
segment. The maggot occurs in numbers in the native huts in the
Congo region and is fairly common in central and northern parts
of Mozambique; it is also recorded from the Zambesi River and the
vicinity of Barberton in the Eastern Transvaal (_Bull. Ent. Res._,
1912, iii, p. 216), in German East Africa, in Nyasaland, and British
East Africa. It is also recorded from Bara, Kordofan,[417] where they
occurred on the floor of the men’s prison and bit the prisoners.
They were destroyed by sprinkling Jeyes’ fluid on the floor. Neave
states (_ibid._, p. 310) that it occurs in the more neglected huts
in native villages throughout tropical Africa, and frequently enters
a tent when pitched near a village. It is also found in West Africa.
The fly is thick-set and about the size and build of a bluebottle
fly; length 10 to 12 mm.; tawny in colour to dirty yellowish-brown,
with dusky hairs, giving it a smoky appearance; the flattened thorax
has long dark stripes and the abdomen a dusky line in the centre of
the second segment, which meets a dark line on its posterior border;
the dusky third segment has a narrow yellowish anterior line; the
fourth segment is also dusky; legs buff with black hairs; the fifth
tarsal segment black. The larvæ are whitish, becoming reddish after
a feast of blood, with much wrinkled skin and rather flat and broad.
They live in crevices of the mud floor, under sleeping mats during
the daytime, and come out at night and suck the blood of sleepers
and then retire to shelter again. Dutton, Todd, and Christy noticed
that where people slept on beds or platforms raised above the floor
the maggots were not so numerous as under the sleeping mats laid on
the ground. They turned up many of the maggots from a depth of three
inches or more.[418]--F. V. T.]

[416] Dutton, Todd and Christy, “The Congo Floor Maggot,” _Mem. xiii Liv. Sch. Trop. Med._, p. 40.

[417] Balfour, _Journ. Trop. Med_., 1909, xii, No. 4, p. 47.

[418] _Journ. Trop. Med._, 1905, viii, No. 6, p. 90.

Family. *Oestridæ.*

[The family of _Oestridæ_ or warble flies are all parasitic in their
larval stage, usually termed the “bot” stage. They are found as
parasites in warm-blooded animals, and man is frequently attacked
by them. The members of this family have the mouth rudimentary,
many of them are hairy and bee-like, with large eyes and the head
large, the lower part more or less swollen. The thorax is large with
a distinct transverse suture, and the abdomen short and stumpy or
very slightly elongated. The male genitalia are hidden, whilst the
female ovipositor is often elongated. The wings may be transparent
(Hypoderma) or mottled (Gastrophilus), and have muscid-like venation;
the tegulæ usually large, the legs moderately long.

[As a rule each species is confined to a particular host, but as we
see recorded here those that attack animals may also attack man.
The flies occur in warm weather and usually during the warmest
part of the day, and have a strong dislike to shade and water. The
genus Hypoderma attack oxen, sheep, goats, antelope and musk deer;
Oestrus, sheep, antelope and horses; Gastrophilus, the horse and
ass; Cephenomyia, the deer; Cepholomyia, the camel and buffalo;
Dermatobia, dogs, cats, oxen, deer, apes and man; Cuterebra and
Rogenhofera, rodents and opossums.

[Some live as parasites in the stomach and intestines (Gastrophilus);
others infest the skin (Hypoderma, Dermatobia and Oestromyia, the
latter on _Lagomys_ and _Hypodæus_); _Œdemagena tarandi_ also infests
the skin of the reindeer in Siberia and boreal America. Oestrus lives
in the nasal sinus, and Cephalomyia in the throat as well, Cuterebra
and Rogenhofera, the skin or scrotum, so that we have really three
groups of parasitic oestride larvæ: (i) cutaneous, (ii) intestinal,
and (iii) facial.

[No species seems confined to man, but the so-called “creeping
disease,” caused by Hypodermæ, and the attack of sheep nasal fly are
comparatively common, as also is the Dermatobia attack.--F. V. T.].

CUTANEOUS OESTRIDÆ.

The eggs are deposited on the surface of the body; the larvæ burrow
in the skin, which they reach after somewhat long peregrination.

Genus. *Hypoderma*, Latreille.

*Hypoderma bovis*, de Geer.

The cattle fly or warble fly, which swarms during the hot season,
settles on the head or on the hair of grazing cattle: through
the young being licked off they gain access to the mouth and are
swallowed.[419] The larvæ appear first in the commencing portion of
the stomach, to escape, as some state, into the preceding sections of
the alimentary canal; at any rate, they are found from July onward
regularly in the submucous tissue of the pharynx, in which they
travel about for several months (up to November, and in isolated
cases up to February); they then penetrate the muscularis and migrate
by way of the subserosa along the mediastinum, the crura of the
diaphragm, the renal capsules, and the intermuscular connective
tissue of the psoas muscle in the direction of the spinal canal,
into which they penetrate by way of the muscles and nerves, through
the intervertebral foramina. Here they stay for about two to three
months, then they leave the spinal canal again through the vertebral
foramina and make their way (from January to March) through the
intermuscular connective tissue of the muscles of the back to the
skin of the back, where sooner or later (from January to June) they
arrive and enter a resting stage, which commences with penetration of
the skin and terminates with outward migration from the boils due to
the wound set up by the maggot. At the commencement of this period
the larvæ cast their skin, and their form, hitherto cylindrical,
becomes oval. After about a month, a second moulting of the skin
takes place--the third larval stage, which lasts about two and a half
months (up to June). The approaching end of the same is indicated
by a change of colour on the part of the larva from the hitherto
yellowish-white to brown and finally to blackish-brown. When they
have become mature the larvæ leave the warbles, drop on to the ground
and pass into the pupal stage in the superficial layers of the soil
within twelve to thirty-six hours. After about a month the flies
emerge. Irregularities with regard to the time and direction of the
migrations of the larvæ take place (Jost, H., in _Zeitschr. f. wiss.
Zool._, 1907, xxxvi, p. 644).

[419] [This is not the case, for Carpenter has shown that muzzled calves become infected (“Mém. First Int. Cong. Ent.,” pp. 289–293). Jost (_Zeitschr. f. wiss. Zool._, 1907, xxxvi, pp. 644–715) thinks that the ova, not young larvæ, are ingested (vide note in Supplement).--F. V. T.]

In a number of cases the larva of the cattle fly has been observed in the human integument, usually in the winter months, that is, during the migration period; consequently, it is not surprising that the larvæ before they enter on the resting stage and produce a warble undergo migrations. But that this takes place subcutaneously--which does not appear to be so in the case of cattle--is perhaps explained by the fact that in man, on account of the short space that has to be traversed, the larvæ are not sufficiently developed to enter on the resting stage simultaneously upon having obtained access to the integument. Whether the Oestrid larvæ in Bulgaria that similarly migrate beneath the skin in man belong to the cattle fly or to another species, or even another genus, has not yet been ascertained. (Doctorow, in _Arch. de Par._, 1906, x, p. 309; Spring, A., in _Bull. Acad. sci. Belg._, 1861 (2), iv, p. 172; Walker, R., in _Brit. Med. Journ._, 1870, i, p. 151; Kjelgaard, in _Ugeskr. f. Laeger_, 1904, p. 535; Condorelli, M., in _Bull. Soc. Zool. Ital._, 1904, xiii, p. 171.)

*Hypoderma lineata*, de Villers.

The larvæ of this species, that occurs not only in Europe but in
North America, live under similar conditions in the skin, very rarely
in man; also migrating subcutaneously (Topsent in _Arch. de Par._,
1901, iv, p. 609).

[In Sweden, the ox warble fly (_H. bovis_) is well known to attack
man. Schoyen states “that over 100 years ago up to the present time
cases of travelling grubs under the human skin in some districts of
Sweden were well known.” The species appeared to be _H. bovis_, many
of which he had examined. They accomplished long ramblings under the
skin, always in an upward direction, previous to their appearance
through an opening in a tumour on the upper part of the body, on the
head, neck, or shoulders. An interesting case is recorded in _Insect
Life_, ii, pp. 238–239. A bot similar to _H. diana_ was taken from
the eye and cheek of a child at Kane, McKean County, Pa., U.S.A. It
was said to have travelled in five months from the elbow to the eye.
Riley later (_Insect Life_, iv, p. 310) was inclined to think the
maggot was that of _H. lineata_, the common American ox warble, which
is also found in Europe in great numbers. I have recorded another
case in England (_Rept. Econ. Zool._ for year ending September 30,
1910, p. 128), where Dr. Menzies removed the larva of _H. bovis_
from the upper eyelid of a patient. It caused considerable swelling
of the face, much pain and distress; but the case did well, and the
wound healed at once. The larva was nearly mature. Numerous other
references to this so-called creeping disease will be found in the
Supplement.

[It is quite probable that _bovis_ and _lineata_ are confused in the
latter accounts. The larvæ are, however, easily distinguished if
carefully examined.--F. V. T.]

*Hypoderma diana*, Brauer.

In its larval stage it lives like other species of Hypoderma,
attacking the red deer (_Cervas elaphas_) and roe deer (_Cervas
capreolus_); it is occasionally also found in man (Joseph, in
“Myiasis externa dermatosa,” Hamburg, 1800; Völkel, in _Berl. klin.
Wochenschr._, 1883, xx, p. 209).

Genus. *Dermatobia*, Brauer.

*Dermatobia cyaniventris*, Macq.

Syn.: _Dermatobia noxialis_, J. Goudot.

The genus Dermatobia represents the subcutaneous _Oestridæ_ of Europe
in warmer parts of America. Both domesticated and wild mammals are
attacked, according to one statement birds also (_Ramphastus_), and
man with fair frequency.[420] It is assumed that in all cases one and
the same species is concerned, for which recently a name originating
from C. Linné, jun. (_Oestrus hominis_), has been employed. Three
larval stages are recognized in the skin; the two first appear to
resemble one another in the club-shaped or tadpole-like appearance
(called macaque in Cayenne, mayacuil [mayoquil] in Mexico), the third
is swollen spindle-shaped (Berne, called torcel). Segments 2 to 4
in the club-shaped larvæ are closely beset with small black spines,
segments 5 to 7 bear at the anterior border a complete ring of strong
black hooks, segments 4 to 6 a similar ring, which, however, is
interrupted at the ventral surface. The four last segments forming
the tail are smooth, only at the posterior end are there small
spines. The arrangement of spines of the third stage differs from
this. Italian workmen that have been employed in Brazil show the
presence of Dermatobia larvæ on their return (Blanchard, in _Bull.
Soc. Ent. France_, 1893, p. 24; _Bull. Soc. centr. de Méd. vet._,
1896; _Ann. Soc. Ent. France_, 1894, lxiii, p. 142; Ward, H. B., in
Mark Annivers. Vol., Article 25, p. 483, New York, 1903).

[420] Duprey advances the opinion that Dermatobia deposits its eggs not only on the skin of man and animals, but also on the leaves and twigs in the bush, where, too, young larvæ have been met with which gain access from hence to men and animals (_Journ. Trop. Med. and Hyg._, 1906).

[_Dermatobia cyaniventris_, Macquart, 1843, is said not to be the
same as _noxialis_ (_vide_ Brauer, “Mono. Oestriden,” 1863, p. 266).
It is known by various other names, as nuche or gusano in New
Granada, the ura in Brazil, and the macaw fly in Cayenne. It occurs
in Central and South America and the West Indies. According to Goudot
the fly is found in great numbers on the borders of large woods and
lands covered with underwood.

[It is seldom that more than one larva is found in each individual.
It is generally found in the arm and leg, but now and then the face.
The perfect insect has never been bred from a larva removed from a
human being, so that there is still uncertainty as to the actual
species. _D. cyaniventris_ is 11 to 12 mm. long, has an ochraceous
buff-coloured face, dark grey thorax, metallic dark blue to purple
abdomen, and brownish wings. _D. noxialis_ is somewhat larger.

[In the _Journal of Tropical Medicine and Hygiene_, January 15, 1905,
viii, p. 23, reference is made to this Oestrid in Trinidad, where
it is called the “mosquito worm.” One case here recorded showed no
fewer than four worms on the chin and one on the hand. It is here
stated that the fly never attacks man or animals directly, as it is
said to do by Scheube, but that the eggs are deposited on leaves and
branches in wooded lands and forests, and thus man, hunting dogs
and wild animals in passing through get the larvæ deposited on them
accidentally. The affection is common in Trinidad. Mention is made
that a little 1 in 40 carbolic lotion syringed into the aperture in
the skin over the worm quickly killed it.

[The cattle worm, or founzaia ngómbe, is the name given to a larva
which develops beneath the skin of oxen and men in Central Africa,
especially amongst the natives and stock of Unyamonezi. According to
P. Dutrieux, the egg is laid by a large fly that accompanies cattle.
It is unknown between the central plateau or the Ugogo and the East
Coast.--F. V. T.]

CAVICOLOUS OESTRIDÆ.

The forms belonging to this group inhabit as larvæ the nasal and frontal sinuses of ruminants, _Equidæ_ and _Proboscidæ_, which they leave for the pupal stage. The larva of--

Genus. *Oestrus*, Linnæus,

*Oestrus* (*Cephalomyia*) *ovis*, L.,

occurring in sheep, has also been observed in man in six cases in the nose and larynx (Saitta in _Gaz. d. Osp. d. Clinic_, 1903, No. 128). So far as is known, the eggs are deposited in the nasal cavity.

[_Oestrus ovis_ frequently occurs in man. MM. Sergent (_Ann. de
l’Inst. Pasteur_, 1907, pp. 392–399) mention that they lay their ova
on the noses, eyes and mouth of humans in Algeria whilst flying,
but that they disappear after three to ten days or the inflammation
produced by them. Portschinsky (_Mem. Bur. Ent. Sci. Com. Cent. Bd.
Land Adm. and Agric._, 1913, x, No. 3, p. 63) also gives cases. He
doubts that ova are laid on the nose; evidently the Russian habit is
anomalous, for the Sergents, Collings and myself find ova laid as a
common occurrence. I have often seen them on the nose of sheep. This
fly also occurs in the Argentine (Serres, in _Gaceta Rural_, April,
1913, vi, pp. 759–761).

[The tamné or thimni of the Kabyles, a human myiasis of the Tuareg
mountains in the Sahara, is caused by _Oestrus ovis_. Here the larvæ
are said to be ejected on to the conjunctival and nasal mucous
membrane of humans.

[Ed. and Lt. Sergent (_Bull. Soc. Path. exot._, 1913, vi, No. 7,
pp. 487–488) report their attack from the Ahaggar mountains, in
Central Sahara. The Tuareg name for the fly, tamné, is the Targui
form of the word thimni used by the Kabyles.--F. V. T.]

GASTRICOLOUS OESTRIDÆ.

The eggs are deposited on the hairs of _Equidæ_, and the larvæ escaping from them are licked up and swallowed. They pass their larval stage, according to the species, in various parts of the intestine and stomach, and when mature, pass out _per anum_ in order to undergo the pupal stage.

Genus. *Gastrophilus*, Leach.

One of the most frequent species is _Gastrophilus equi_, Fabr.;
the eggs are laid on the hairs; the larvæ live some ten months in
the stomach, living attached to the inner surface. The eggs of _G.
hæmorrhoidalis_, L., are deposited on the lips or the long hairs on
them. The larvæ adhere to the cardiac end of the stomach, to the
stomach itself, and finally to the terminal portion of the intestine.
Here, however, and elsewhere in the intestine, the larvæ of _G.
pecorum_, Fabr., are also met with, whilst the larvæ of _G. nasalis_
(so called because the eggs are deposited in the nasal orifices)
almost exclusively inhabit the anterior section of the duodenum.

Cholodkowsky attributes the “wormlet” observed by Samson and Sokolew
(_Wratsch_, 1895, Nos. 48 and 57) and others (_ibid._, 1896–98)
to _Gastrophilus_ larvæ. It burrows into the epidermis of man by
minute passages. This observation should, however, be verified. The
phenomenon is designated as skin-mole, larva migrans, and creeping
eruption.

OTHER PAPERS ON DIPTEROUS LARVÆ, ETC., IN MAN.

(1) “Ein Fall von lebenden Fliegenlarven im menschlichen Magen,”
_Deutsch med. Wochenschr._, Leipz. and Berl., xxiv (12), pp. 193–194.
Bachmann, and review of same, “Living Fly Larvæ in the Human
Stomach,” _Philadelphia Med. Journ._, 1898, i, 18, p. 773.

(2) “Sudi una larva di dittero parassita della congiuntiva umana,”
_Ann. di ottal._, Paira, 1895, xxiv (4), pp. 329–336, 1 fig., E.
Baquis.

(3) “Sur quelques diptères suceurs de sang, observé à Terre-Neuve,”
_Arch. de Par._, Paris, 1900, iii (1), pp. 202–204, E. Barret.

(4) “An Account of the Larvæ of two Species of Insects discharged
from the Human Body,” _Edin. Med. and Surg. Journ._, January 1, 1811,
vii (25), pp. 41–48, 1 pl., figs. 1 to 8, T. Bateman.

(5) “Un cas de myiase par la _Sarcophaga magnifica_ en Roumanie,”
_Bull. Soc. Zool. de France_, Par., 1891, xvi (2), pp. 25–26, R.
Blanchard.

(6) “Sur les oestrides américains dont la larve vit dans la peau
de l’homme,” _Ann. Soc. ent. de France_, 1892, v, pp. 109–154,
figs. 1–12, R. Blanchard.

(7) “Note additionnelle sur les oestrides américans dont la larve vit
dans la peau de l’homme,” _Bull. Soc. ent. de France_, Paris, 1894,
xiv, pp. 209–211, R. Blanchard.

(8) “Note sur des larves de Dermatobia provenant de Brésil,” _Bull.
Soc. ent. de France_, Paris, 1893 (2), pp. 24–27, R. Blanchard.

(9) “Larven der Wohlfahrtfliege (_Sarcophila wolfahrtii_) im
Zahnfleische eines Menchen,” _Wratsch._, St. Petersburg, 1888, 5–6,
E. K. Brandt.

(10) “Ueber den sogenannten _Oestrus hominis_ und die oftmals
besichteten Verirrungen von Oestriden der Säugetheiere zum Menchen,”
_Verhandl. d. k. zool.-bot. Gesellsch._, 1860, x Abhandl., pp. 57–72,
Brauer.

(11) “Ueber die Larven der Gattung Cuterebra, Clk.,” _Verhandl. d. k.
zool.-bot. Gesellsch._, 1860, x Abhand., pp. 777–786, Brauer.

(12) “Des désordres produits chez l’homme par les larves de la
_Lucilia hominivorax_,” _Thèse_, Paris, 1864, 43 pp., V. Audouit.

(13) “Note on the ‘Flesh Worm,’” _Med. Press and Circ._, London,
April 12, 1882, lxxxii (N.S. xxxiii), p. 314, P. S. Abraham.

(14) “Larvas de la _Calliphora limensis_ en fosas nasalis,” 1855, 18
pp., F. Aguirre.

(15) “Raro caso di parasitismo nell ’uomo dovuto alla larva di una
mosca (_Sarcophaga affinis_, Meigen),” _Boll. d. Soc. Rom. per gli
Stud. Zool._, Roma, 1893, iv (5–6), pp. 278–289, 1 pl., 3 figs.,
Giulo Alessandrini.

(16) “Observations sur l’espèce de ver nommé Macaque (Oestrus),”
_Mém. Acad. Sci. par Hist._, 1753, p. 72, F. Artur.

(17) “Contribuição ao estudo da biologia da _Dermatobia
cyaniventris_,” _Trav. do Inst. de Manguinhos_, 1908.

BITING-MOUTHED AND OTHER NOXIOUS DIPTERA WHICH MAY BE DISEASE CARRIERS.

[Amongst the division _Brachycera_ (as meant in this work) we get
several groups of flies which, like the fleas and mosquitoes, are
partially parasitic on man, the adults, mainly in the female sex,
being provided with a piercing mouth with which they extract the
blood of man and animals. The importance of these parasites is not
the mere fact that they feed upon our blood, but that they often
carry germs from man to man (tsetse-flies and trypanosomiasis,
_Tabanidæ_ and anthrax). Amongst the most important biting-mouthed
_Diptera_ in this section are the following: _Tabanidæ_, or
gad-flies; _Glossinæ_, or tsetse-flies; and certain other _Muscidæ_.
Some of the exotic _Asilidæ_ and a few _Leptidæ_ also bite man.

Family. *Tabanidæ* (Gad-flies).

[The _Tabanidæ_ have a broad, rather flattened body and a large head;
eyes united in the male (except in some Chrysops). The antennæ are
composed of three segments, have the third joint composed of five
to eight annuli--in Chrysops they are fairly long. The proboscis is
projecting, and sometimes much elongated. The legs are moderately
stout. The venation of the wings is shown in fig. 415.

[This family of gad or horse flies contains a great number of genera,
all of which may bite animals and man more or less severely. The
female alone is blood-sucking, the males feed upon the juices of
flowers. The females deposit their spindle-shaped white, black,
or brown eggs on leaves, stems of plants that either overhang or
stand in water, and amongst rushes; they are at first white, but
become brown or black. The eggs are laid in rounded, flattened or
conical masses composed of layers one upon the other. The larvæ are
carnivorous, feeding upon snails, worms, other larvæ, etc., and have
a distinct head; they are cylindrical, composed of eleven segments,
the last with a vertical breathing pore, or the last two segments may
form a breathing tube. The majority taper to a point at each end, in
colour shining white or dull grey to yellowish, many of the larger
specimens mottled or banded with dark brown or black. The first seven
abdominal segments are encircled near the anterior margin with a
ring of fleshy protuberances consisting of a transverse dorsal ridge
which may be divided by a depression into two. The young larvæ burrow
into any soft vegetable substance; they live both in the water and
under damp soil surrounding water, also in damp earth generally. The
larvæ are not only carnivorous, but they are cannibals, frequently
devouring their own species. They may take more than a year to mature.

[The pupæ are found close to the surface of mud and earth, and are
mostly dull yellowish to brown in colour, with rows of spines on the
distal third of each abdominal segment; the thorax bears a pair of
ear-shaped spiracular structures, and there are also six denticles at
the apex of the abdomen.

[A habit common to the adults of most of the _Tabanidæ_ of
considerable economic importance is that of the adults coming to
water to drink. Portschinsky[421] has found that by applying kerosene
to the pool they frequent the adults are killed, and Hine[422] that
the same oil kills the larvæ that fall into the water from eggs laid
on plants above.

[421] _Vide Bull._ 20, _N. Sc., U.S. Div. Ent._

[422] “_Tabanidæ_ of Ohio,” _Ohio State University Bull._ 19, 1903, sec. 7, p. 14.

[_Tabanidæ_ are not only of importance as purely biting insects,
for they may often convey pathogenic organisms from one animal to
another, such as the bacillus of anthrax, which they are known to
carry, and possibly also trypanosomes in regard to man. Chrysops also
acts as a host of _Filaria loa_ in South Nigeria (Leiper, _Brit. Med.
Journ._, January, 1912, pp. 39–40). Two species are incriminated,
_viz._, _C. silacea_ and _C. dimidiata_. With animals these flies
play a more important part, for MM. Sergent, in Algeria, have proved
that species of Tabanus are able to transmit three forms of animal
trypanosomes by biting a healthy animal as long as twenty-two hours
after having bitten an unhealthy one. In India they have also been
shown to transmit the parasite of “surra” in dogs and rabbits by
Rogers. Other observers have since corroborated these results,
and Mitzmain, who has recently performed valuable work in this
connection, states that _T. striatus_ is undoubtedly the carrier
of this disease in the Philippine Islands. Certain members of the
genus Hæmatopota have also been shown to be capable of the direct
transmission of _Trypanosoma evansi._ Martoglio (_Ann. d’Ig. sper._,
1913, xxiii, N.S., No. 3, pp. 363–366) states that the trypanosome
disease of dromedaries known as salaf is transmitted by _Tabanidæ_,
especially Pangonia (_P. magretti_ and _P. beckeri_) in Italian
Somaliland. It is quite likely that these flies play a much greater
part in the spread of such diseases than is imagined at the present
time.

[The _Tabanidæ_ are divided into two groups or subfamilies: (1) The
_Pangoninæ_, and (2) the _Tabaninæ_; the former have spurs on the
hind tibiæ and usually ocelli; the latter have neither tibial spurs
nor ocelli.

[The _Pangoninæ_ contain two main genera, Pangonia and Chrysops. In
the former the proboscis is much elongated, and the third antennal
segment is composed of eight rings, and is never angulated or
ungulated at the base. The proboscis is often very long.

[In Chrysops, the so-called blinding storm flies, all the three
segments of the antennæ are long, the third having only five
annulations, and the proboscis short but very strong.

[There are many genera in the _Tabaninæ_, which are found in all
parts of the world, of which two only are shown here--_viz._,
Tabanus and Hæmatopota. The former has the first two segments of the
antennæ short, the third angulated at the base, sometimes spurred
and composed of five annulations; the second has the second segment
short, and the third composed of four annulations--never angulated
nor spurred at the base--and the wings are adorned with grey or brown
markings. These latter are usually called “brimps” and “clegs” in
Britain, the former gad or horse flies, the seruts and mangrove flies
of tropical countries.

Family. *Asilidæ* (Wolf Flies).

[These flies are of little importance in regard to the subject dealt
with in this book; but I have notes sent concerning the biting habits
of one or more species belonging to this family from the Malay States
and Africa.

[_Asilidæ_, or wolf flies, are easily told by the following
characters: Large or moderate-sized flies, thickly hairy; head
separated from thorax by a narrow neck; eyes separated in both
sexes; proboscis firm and horny, adapted for piercing; abdomen long,
pointed, and composed of eight segments. Legs strong and bristly,
of moderate length. Wings sometimes mottled, lying parallel over
the abdomen when at rest. There are nearly 3,000 species. They live
mostly upon insects, but some are said to bite animals and man. They
are, however, of little importance in this respect.

Family. *Leptidæ.*

[This widely distributed family of flies has a few species which suck
the blood of man, and the writer has been personally badly bitten in
Norway by a Leptis which was apparently _Leptis scolopacea_.

[The _Leptidæ_ have usually blotched wings and similar venation to
Tabanus; they are elongated flies of moderate or large size, and of
dull colours. The antennæ are varied and consist of three segments,
either with or without a terminal bristle or with the third segment
compound, and in a few they may be almost nematocerous. The wing
veins are distinct, very crowded anteriorly, the third long vein is
furcate, basal cells large, and there are usually five posterior
cells, the anal cell being open in some; the squamæ are always small,
sometimes only rudimentary.

[Four are known to be blood-suckers, namely the American
Symphoromyia, _Trichopalpus obscurus_ in Chili, and _Leptis strigosa_
and _L. scolopacea_ in Europe. The genus Symphoromyia has a single
spur on the hind tibiæ, none on the fore or mid tibiæ, the third
segment of the three-ringed antennæ kidney-shaped, and a short
proboscis. In the genus Leptis the hind tibiæ have two spurs, and the
third antennal segment is not reniform.

[The other biting genus Trichopalpus can be told at once by the
elongated proboscis. Most of this family live upon other insects. The
larvæ live in earth, decaying wood, sand, stagnant waters, and the
nests of wood-boring beetles; they are usually cylindrical and may
have fleshy abdominal legs; the anal segment has a transverse cleft,
and often two posteriorly directed processes and two stigmata between
them. They are all predaceous, and in one genus (Vermileo) make
pitfalls in sand like the ant lions (_Myrmeleon_).

Blood-sucking Muscidæ.

[The blood-sucking _Muscidæ_ are mainly contained in the following
genera: Glossina, Stomoxys, Hæmatobia, Lyperosia, Stygeromyia,
Philæmatomyia and Bdellolarynx.

[The first is the most important genus on account of the part it
plays in the spread of trypanosome diseases. Stomoxys may also serve
as a disease carrier. The remainder and a few more genera cause
considerable annoyance by their bites, and may also act as occasional
carriers of pathogenic organisms. All these flies have their mouth
parts elongated to some extent, forming a distinct proboscis, which
becomes more or less strongly chitinized; the labella are usually
serrated or spiny, and thus form a structure easily capable of
piercing the skin. Unlike the _Culicidæ_, the blood-sucking _Muscidæ_
have the sanguinary habit common to both sexes.

Genus. *Glossina*, Westwood.

[This genus contains sixteen species,[423] all of which are
confined to the Ethiopian region. Glossina may be distinguished
from other allied genera by the proboscis, the antennæ, wings, and
male genitalia. The proboscis projects forwards and has a swollen
bulb-like base to the slender labium which holds the two structures,
the needle-like epipharynx and the thread-like hypopharynx; the whole
proboscis is ensheathed in the maxillary palpi. The antennæ have the
first two segments small, the third large with a marked pore, the
orifice of the sense organ near the base; from the base of the third
segment also arises the three-jointed arista, the first two segments
being, however, minute; the third bears a series of from seventeen
to twenty-one fine branched hairs on one side. The male genitalia or
hypopygium is more or less oval and tumid, its long axis lying in the
antero-posterior direction, with a vulviform median groove (the anus)
running from the anterior margin to beyond the middle.

[423] This does not include _G. maculata_, Newstead, which is regarded by Austen as a synonym of _G. palpalis_, Rob. Des.; according to this authority the curiously spotted appearance of the type and only example of _G. maculata_ is due to foreign matter.

[Newstead has shown the importance of the study of the genitalia
in separating species (_vide_ _Bull. Ent. Res._, ii, pp. 9–36 and
107–110, and iii, pp. 355–360; and _Ann. Trop. Med. and Par._, vii,
No. 2, pp. 331–334).

[The tsetse-flies reproduce differently from all other _Muscidæ_. The
female produces at each birth a single full-grown larva, which is
retained within the oviduct and there nourished by the secretion of
special glands, and on being born crawls to some hiding place and at
once becomes a puparium.

[The larva is a yellowish footless maggot nearly as large as the
mother’s body, the skin shagreened and the anal extremity having a
pair of large, black, granular prominences separated by a depression
containing the breathing pores.

[The puparium is brown of various shades, the tumid lips of the
larva being conspicuous, the size and shape of the lips enabling the
puparia to be identified.