THE HOUSE FLY AND ITS ALLIES.
[Illustration: 84. Mouth-parts of the House fly.]
The common House fly, Musca domestica, scarcely needs an introduction to
any one of our readers, and its countenance is so well known that we
need not present a portrait here. But a study of the proboscis of the
fly reveals a wonderful adaptability of the mouth-parts of this insect
to their uses. We have already noticed the most perfect condition of
these parts as seen in the horse fly. In the proboscis of the house fly
the hard parts are obsolete, and instead we have a fleshy tongue like
organ (Fig. 84), bent up beneath the head when at rest. The maxillæ are
minute, their palpi (_mp_) being single-jointed, and the mandibles (_m_)
are comparatively useless, being very short and small, compared with the
lancet-like jaws of the mosquito or horse fly. But the structure of the
tongue itself (labium, l) is most curious. When the fly settles upon a
lump of sugar or other sweet object, it unbends its tongue, extends it,
and the broad knob-like end divides into two broad, flat, muscular
leaves (_l_), which thus present a sucker-like surface, with which the
fly laps up liquid sweets. These two leaves are supported upon a
framework of tracheal tubes. In the cut given above, Mr. Emerton has
faithfully represented these modified trachæ, which end in hairs
projecting externally. Thus the inside of this broad fleshy expansion
is rough like a rasp, and as Newport states, "is easily employed by the
insect in scraping or tearing delicate surfaces. It is by means of this
curious structure that the busy house fly occasions much mischief to the
covers of our books, by scraping off the albuminous polish, and leaving
tracings of its depredations in the soiled and spotted appearance which
it occasions on them. It is by means of these also that it teases us in
the heat of summer, when it alights on the hand or face to sip the
perspiration as it exudes from, and is condensed upon, the skin."
[Illustration: 85. Larva; _a_, Pupa-case of House fly.]
[Illustration: 86. Larva of Flesh fly.]
Every one notices that house flies are most abundant around barns in
August and September, and it is in the ordure of stables that the early
stages of this insect are passed. No one has traced the transformations
of this fly in our country, but we copy from Bouché's work on the
transformations of insects, the rather rude figures of the larva (Fig.
85), and pupa-case (_a_) of the Musca domestica of Europe, which is
supposed to be our species. Bouché states that the larva is cylindrical,
rounded posteriorly, smooth and shining, fleshy, and yellowish white,
and four lines long. The pupa-case, or puparium, is dark reddish-brown,
and three lines in length. It remains in the pupa state from eight to
fourteen days. In Europe it is preyed upon by minute ichneumon flies
(Chalcids). The flesh fly, Musca Cæsar, or the Blue-bottle fly, feeds
upon decaying animal matter. Its larva (Fig. 86) is long, cylindrical,
the head being pointed, and the body conical, the posterior end being
squarely docked. The larva of a Sargus-like form which feeds on offal,
transforms into a flattened pupa-case (Fig. 87), provided with long,
scattered hairs. The House fly disappears in autumn, at the approach of
cold weather, though a few individuals pass through the winter,
hibernating in houses, and when the rooms are heated may often be seen
flying on the windows. Other species fly early in March, on warm days,
having hibernated under leaves, and the bark of trees, moss, etc. An
allied species, the M. vomitoria, is the Meat fly. Closely allied are
the parasitic species of Tachina, which live within the bodies of
caterpillars and other insects, and are among the most beneficial of
insects, as they prey on thousands of injurious caterpillars. Another
fly of this Muscid group, the Idia Bigoti, according to Coquerel and
Mondiere, produces in the natives of Senegal, hard, red, fluctuating
tumors, in which the larva resides.
[Illustration: 87. Larva of a Sargus-like fly.]
Many of the smaller Muscids mine leaves, running galleries within the
leaf, or burrowing in seeds or under the bark of plants. We have often
noticed blister-like swellings on the bark of the willow, which are
occasioned by a cylindrical, short, fleshy larva (Fig. 88_a_, much
enlarged), about a line in length, which changes to a pupa within the
old larval skin, assuming the form here represented (Fig. 88_b_), and
about the last of June changes to a small black fly (Fig. 88), which
Baron Osten Sacken refers doubtfully to the genus Lonchæa.
[Illustration: 86. Willow Blister fly.]
The Apple midge frequently does great mischief to apples after they are
gathered. Mr. F. G. Sanborn states that nine-tenths of the apple crop in
Wrentham, Mass., were destroyed by a fly supposed to be the Molobrus
mali, or Apple midge, described by Dr. Fitch. "The eggs were supposed to
have been laid in fresh apples, in the holes made by the Coddling moth
(Carpocapsa pomonella), whence the larvæ penetrated into all parts of
the apple, working small cylindrical burrows about one-sixteenth of an
inch in diameter." Mr. W. C. Fish has also sent me, from Sandwich,
Mass., specimens of another kind of apple worm, which he writes has been
very common in Barnstable county. "It attacks mostly the earlier
varieties, seeming to have a particular fondness for the old fashioned
Summer, or High-top Sweet. The larvæ (Fig. 89 _a_) enter the fruit
usually where it has been bored by the Apple worm (Carpocapsa), not
uncommonly through the crescent-like puncture of the curculio, and
sometimes through the calyx, when it has not been troubled by other
insects. Many of them arrive at maturity in August, and the fly soon
appears, successive generations of the maggots following until cold
weather. I have frequently found the pupæ in the bottom of barrels in a
cellar in the winter, and the flies appear in the spring. In the early
apples, the larvæ work about in every direction. If there be several in
an apple, they make it unfit for use. Apples that appear perfectly sound
when taken from the tree, will sometimes, if kept, be all alive with
them in a few weeks." Baron Osten Sacken informs me that it is a
Drosophila, "the species of which live in putrescent vegetable matter,
especially fruits."
[Illustration: 89. Apple Worm and its Larva.]
[Illustration: 90. Parent of the Cheese Maggot.]
[Illustration: 91. Pupa case of Wine-fly.]
An allied fly is the parent of the cheese maggot. The fly itself
(Piophila casei, Fig. 90) is black, with metallic green reflections, and
the legs are dark and paler at the knee-joints, the middle and hind pair
of tarsi being dark honey yellow. The Wine fly is also a Piophila, and
lives the life of a perpetual toper in old wine casks, and partially
emptied beer, cider and wine bottles, where, with its pupa-case (Fig.
91), it may be found floating dead in its favorite beverage.
[Illustration: 92. Bird Tick.]
We now come to the more degraded forms of flies which live parasitically
on various animals. We figure, from a specimen in the Museum of the
Peabody Academy of Science, the Bird tick (Ornithomyia, Fig. 92), which
lives upon the Great Horned Owl. Its body is much flattened, adapted for
its life under the feathers, where it gorges itself with the blood of
its host.
[Illustration: 93. The Horse Tick.]
Here belongs also the Horse tick (Hippobosca equina, Fig. 93). It is
about the size of the house fly, being black, with yellow spots on the
thorax. Verrill[4] says that "it attacks by preference those parts where
the hair is thinnest and the skin softest, especially under the belly
and between the hind legs. Its bite causes severe pain, and will
irritate the gentlest horses, often rendering them almost unmanageable,
and causing them to kick dangerously. When found, they cling so firmly
as to be removed with some difficulty, and they are so tough as not to
be readily crushed. If one escapes when captured, it will instantly
return to the horse, or, perchance, to the head of its captor, where it
is an undesirable guest. Another species sometimes infests the ox."
[Illustration: 94. Sheep Tick.]
[Illustration: 95. Bat Tick.]
In the wingless Sheep tick (Melophagus ovinus, Fig. 94, with the
pupa-case on the left), the body is wingless and very hairy, and the
proboscis is very long. The young are developed within the body of the
parent, until they attain the pupa state, when she deposits the pupa
case, which is nearly half as large as her abdomen. Other genera are
parasitic on bats; among them are the singular spider-like Bat ticks
(Nycteribia, Fig. 95), which have small bodies and enormous legs, and
are either blind, or provided with four simple eyes. They are of small
size, being only a line or two in length. Such degraded forms of Diptera
have a remarkable resemblance to the spiders, mites, ticks, etc. The
reader should compare the Nycteribia with the young six-footed moose
tick figured farther on. Another spider-like fly is the Chionea valga
(Fig. 96; and 97, larva of the European species), which is a degraded
Tipula, The latter genus standing near the head of the Diptera. The
Chionea, according to Harris, lives in its early, stages in the ground
like many other gnats, and is found early in the spring, sometimes
crawling over the snow. We have also figured and mentioned previously
(page 41) the Bee louse, Braula, another wingless spider-like fly.
[Illustration: 96. Spider fly.]
[Illustration: 97. Larva of Spider fly.]
The Flea is also a wingless fly, and is probably, as has been suggested
by an eminent entomologist, as Baron Osten Sacken informs us, a degraded
genus of the family to which Mycetobia belongs. Its transformations are
very unlike those of the fly ticks, and agree closely with the early
stages of Mycetophila, one of the Tipulid family. In its adult condition
the flea combines the characters of the Diptera, with certain features
of the grasshoppers and cockroaches, and the bugs. The body of the flea
(Fig. 98, greatly magnified; _a_, antennæ; _b_, maxillæ, and their
palpi, _c_; _d_, mandibles; the latter, with the labium, which is not
shown in the figure, forming the acute beak) is much compressed, and
there are minute wing-pads, instead of wings, present in some species.
[Illustration: 98. Flea, magnified.]
[Illustration: 99. Larva of Flea.]
Dr. G. A. Perkins, of Salem, has succeeded in rearing in considerable
numbers from the eggs, the larvæ of this flea. The larvæ (Fig. 99, much
enlarged; _a_, antenna; _b_, the terminal segments of the abdomen), when
hatched, are half a line in length. The body is long, cylindrical, and
pure white, with thirteen segments exclusive of the head, and provided
with rather long hairs. It is very active in its movements, and lives on
blood clots, remaining on unswept floors of out-houses, or in the straw
or bed of the animals they infest. In six days after the eggs are laid
the larvæ appear, and in a few days after leaving the egg they mature,
spin a rude cocoon, and change to pupæ, and the perfect insects appear
in about ten days. A good authority states that the human flea does not
exist in America. We never saw a specimen in this country.
A practical point is how to rid dogs of fleas. As a preventive measure,
we would suggest the frequent sweeping and cleansing of the floors of
their kennels, and renewing the straw or chips composing their
beds,--chips being the best material for them to sleep upon. Flea
afflicted dogs should be washed every few days in strong soapsuds, or
weak tobacco or petroleum water.
A writer in "Science-Gossip" recommends the "use of the Persian Insect
Destroyer, one package of which suffices for a good sized dog. The
powder should be well rubbed in all over the skin, or the dog, if small,
can be put into a bag previously dusted with the powder; in either case
the dog should be washed soon after."
[Illustration: 100. Chique.]
One of the most serious insect torments of the tropics of America is the
Sarcopsylla penetrans, called by the natives the Jigger, Chigoe, Bicho,
Chique, or Pique (Fig. 100, enlarged; a, gravid female, natural size).
The female, during the dry season, bores into the feet of the natives,
the operation requiring but a quarter of an hour, usually penetrating
under the nails, and lives there until her body becomes distended with
eggs, the hind-body swelling out to the size of a pea; her presence
often causes distressing sores. The Chigoe lays about sixty eggs,
depositing them in a sort of sac on each side of the external opening of
the oviduct. The young develop and feed upon the swollen body of the
parent flea until they mature, when they leave the body of their host
and escape to the ground. The best preventive is cleanliness and the
constant wearing of shoes or slippers when in the house, and of boots
when out of doors.
[Illustration: The Willow Gall Fly.]