These insects are generally of much larger size, and more robust in
appearance than those contained in the previous tribe. They are divided
into twenty-two families.
[Illustration: Fig. 133.--Stratiomys Chameleon.]
_Family 13, Xylophagidæ._--The _Xylophagidæ_ are thick-looking insects.
The head is as broad as the thorax. The legs, which are long and
slender, are quite naked. The _larvæ_ live in rotten wood, and the
flies may often be seen at rest on the trunks of trees.
[Illustration: Fig. 134.--Sargus Cuprarius (Mag.)]
_Family 14, Cœnomyiidæ._--In this family the head is narrower than
the thorax; otherwise they closely resemble the previous family. The
typical European species is _Cœnomyia ferruginea_, which measures
about three-quarters of an inch in length, and in colour varies from
rusty-yellow to black. The _larvæ_ feed inside the trunks of rotten
poplars.
_Family 15, Stratiomyiidæ._--These are rather slender flies, varying
from half to one inch in length. They are usually found resting on low
plants. Many species frequent cow-dung and manure, etc. Several kinds
exhibit a metallic coloration, others are black, often more or less
varied with white or yellow.
[Illustration: Fig. 135.--Chrysops Cæcutriens (Mag.)]
_Family 16, Acanthomeridæ._--The _Acanthomeridæ_ are met with
principally in America. The typical species, _Acanthomera picta_, is
found in Brazil, and measures more than an inch in length. It used
formerly to be largely used in the manufacture of pomade.
_Family 17, Tabanidæ._--The _Tabanidæ_ are broad-looking insects. The
_larvæ_ usually live in damp earth. The females of these species live
on the blood of animals.
The best-known species is the Gad Fly (_Tabanus bovinus_), which
measures more than an inch in length, and is particularly troublesome
to cattle in hot weather. It is blackish above, and reddish beneath and
on the sides of the abdomen.
The Clegg Fly (_Hæmatopota pluvialis_) also belongs to this family. It
is a dingy-looking insect with mottled-grey wings, and is sometimes
very abundant in damp meadows.
[Illustration: Fig. 136.--Hæmatopota Pluvialis (Mag.)]
Many other species of _Tabanidæ_, popularly called "Breeze Flies," are
plentiful in this country.
_Family 18, Leptidæ._--These insects are mostly predatory, though many
small species are parasitic on animals and other insects. The _larva_
of _Vermilio degeerii_ lives in sand, and feeds on such insects
as fall in its way. Those of the genus _Leptis_ are parasitic on
cockchafers and other large beetles.
[Illustration: Fig. 137.--Vermilio Degeerii (Mag.)]
[Illustration: Fig. 138.--Chrysopila Atrata (Mag.)]
_Family 19, Asilidæ._--The _Asilidæ_ or Hawk Flies are a family of
considerable extent, and include many very large and conspicuous
insects. They feed on other insects, and are very courageous, sometimes
attacking even dragon flies. One of the most common species is _Asilus
crabroniformis_, which is common in the south of England.
_Family 20, Midaidæ._--These are large insects resembling the _Asilidæ_
in their habits, and are nearly all tropical. A few species, however,
inhabit the south of Europe.
_Midas giganteus_ is found in Brazil and adjacent countries in tropical
America. It measures about one inch and a half in length.
_Family 21, Nemestrinidæ._--These insects are chiefly inhabitants of
tropical climates like the preceding family. They are generally of
a black colour, sometimes with red legs. They suck the nectar of
flowers through a long proboscis, but nothing is yet known of their
transformations.
[Illustration: Fig. 139.--Xylophagus Ater (Mag.)]
[Illustration: Fig. 140.--Ceria Conopsoides (Mag.)]
_Family 22, Bombyliidæ._--The Bee Flies belong to this family. They
are small or middle-sized insects, densely clothed with hairs. They
are exceedingly active insects with long tongues, with which they suck
honey from flowers. Their _larvæ_ are often parasitic in their earlier
stages on other insects.
They are very useful in North America by keeping down the number of
locusts, in the egg capsules of which the _larvæ_ feed.
Two species, _Bombyliis major_ and _B. medius_, are common in this
country, and may often be seen in gardens and open spaces in woods
during the spring and summer months.
_Family 23, Therevidæ._--This family is a very numerous one, especially
those of the typical genus _Thereva_. They are slender, middle-sized
black insects, and their bodies are generally covered with hair. They
are generally found in the neighbourhood of bushes and trees.
_Family 24, Scenopinidæ._--The _Scenopinidæ_ include a few minute,
black flies, not exceeding a quarter of an inch in length. They are not
very common, but are sometimes found about windows.
_Family 25, Scroceridæ._--This family also contains small species of
flies, but their metamorphoses are at present unknown.
[Illustration: Fig. 141.--Medeterus Nolatus (Mag.)]
They are usually to be found resting easily on dry branches of trees,
but are generally rare.
_Family 26, Empididæ._--The insects of this group are very similar to
the _Asilidæ_ in their carnivorous propensities, but the species are
usually of a much smaller size. _Empis livida_ is a common yellowish
species measuring about one-third of an inch in length.
[Illustration: Fig. 142.--Dolichopus Regalis (Mag.)]
_Family 27, Dolichopodidæ._--This family is a very extensive one,
including a considerable number of genera and species. They are usually
small flies often of brilliant metallic colouring. They may be found
generally in the neighbourhood of water.
[Illustration: Fig. 143.--Scenopinus Fenestralis (Mag.)]
_Family 28, Lonchopteridæ._--The species of _Lonchopteridæ_ are small
yellowish-brown or greenish flies with lanceolate wings. They frequent
the banks of shady streams, and are often found resting on wet stones.
_Family 29, Syrphidæ._--The majority of flies belonging to this family
are of a moderate size, and possessed of brilliant colours. With the
exception of the enormous family _Muscidæ_, they are one of the largest
families of the _Diptera_.
[Illustration: Fig. 144.--Syrphus Ribesii (Mag.)]
Most of the species may be recognised at once by their peculiar mode of
flight, for they hover motionless in the air, and if alarmed dart off
with a rapid motion which the eye cannot follow.
_Milesia Crabroniformis_ is a very large species common in the south of
Europe.
About thirty species are found in the British Isles. Of these _Syrphus
pyrastri_ is perhaps the best-known example. It is a very wasp-like
creature, and is, indeed, mistaken by many people for a wasp. It is
a very useful insect, feeding largely on aphides and plant lice, and
should therefore be encouraged by every horticulturist.
_Family 30, Conopidæ._--The _larvæ_ of most of these insects are
parasitic on _Orthoptera_ and _Hymenoptera_. Many species have a
resemblance to wasps in appearance, being striped with yellow and
black. The typical genus, _Conops_, are slender flies measuring half an
inch in length.
_Family 31, Pipunculidæ._--These are black or brown insects. The head
is large and round, generally broader than the thorax. The _larvæ_ are
mostly parasitic on other insects. The flies may often be seen in great
swarms in shady places in the vicinity of hedges, in lanes, etc.
_Family 32, Platypezidæ._--This family contains many beautiful flies.
Great numbers of them are marked with orange and silver and black. The
_larvæ_ inhabit fungi.
[Illustration: Fig. 145.--Eristalis Simili (Mag.)]
_Family 33, Æstridæ._--The Bot Flies are well known on account of the
annoyance they cause to cattle. They lay their eggs upon the hides
of the animals, and the _larvæ_, when hatched, make their way under
the skin, and there take up their abode, living on the juices of
their unfortunate host. It is estimated that the loss occasioned by
these troublesome pests amounts to millions of pounds in the British
Isles alone. The best-known species is probably _Æstrus bovis_, which
infests the ox. The cattle are so well aware of the danger attending
the presence of this insect, that as soon as it appears near them, the
whole herd exhibits the most unmistakable signs of terror, rushing
about their pasture with their tails in the air, and in case of need
taking refuge in water, where the fly will not follow them. Miss E.
A. Ormerod has recently paid much attention to the economy of this
insect, with the view to finding some remedy for its attacks.
[Illustration: Fig. 146.--Nemestrina Longirostris (Mag.)]
_Family 34, Muscidæ._--The _Muscidæ_ is the most numerous family, of
the _Diptera_ and it includes many familiar insects. It is divided
into two sections, containing thirteen sub-families. The first
section, _Calypteræ_, contains five sub-families. The _Tachininæ_ are
parasitic in the larval stage on _Lepidoptera_. The largest of the
_Muscidæ_ found in Europe is _Echinomyria grossa_, which measures about
three-quarters of an inch in length.
[Illustration: Fig. 147.--Volucella Zonaria.]
[Illustration: Fig. 148.--Conops Flavipes (Mag.)]
[Illustration: Fig. 149.--Myopa Ferruginea (Mag.)]
Many species of the _Dexinæ_ are of the most metallic-green or blue.
They are principally found in Australia.
The Flesh Fly (_Sarcophaga carnaria_) belongs to the _Sarcophaginæ_ and
is one of our largest species. The _larvæ_ of some species are called
"Screw Worms" in America.
The fourth sub-family, the _Muscinæ_, contains the most typical species
of the _Diptera_ or two-winged flies. The common House Fly (_Musca
domestica_) is the most familiar example. Several blue-and-green flies
are produced from _larvæ_ which feed on more or less putrid flesh,
and are well known to anglers as "Gentles." The Blow Fly or Blue
Bottle (_Musca vomitoria_) is one of these, also the Green Bottle Fly
(_Lucilia Cæsar_) which is often common about hedges in the summer
time. Many species belong to the sub-family _Anthomyiinæ_, are very
small insects, and their _larvæ_ mine in the leaves of plants like
those of _Tineæ_.
[Illustration: Fig. 150.--Platypeza Fasciata (Mag.)]
[Illustration: Fig. 151.--Gastrophilus Equi (Mag.)]
Section 2, namely _Acalypteræ_, contains eight sub-families.
The species of _Scalophaginæ_ are usually called "Dung-flies." The
commonest species, the Yellow Dung Fly (_Scatophaga stercoraria_),
feeds largely on manure and other refuse.
The _Ortalinæ_ are flies of small or moderate size, which are met with
principally in woods and fields. The _Trypetinæ_ feed chiefly on fruit.
One species, _Ceratitis hispanica_, is very destructive to oranges in
the south of Europe, etc. Of the _Piophilinæ_, _Piophila casei_ may be
taken as the typical example. The _larvæ_ which abound in cheese and
bacon are popularly called "Cheese Hoppers," or "Jumpers," in allusion
to their habit of springing. The _Diopsinæ_ are principally met with
in the tropical parts of the world. They are generally insects of
moderate size. Most of the species of _Chloropinæ_ are of small size.
Their _larvæ_ generally live in the stems of corn and various kinds of
grasses. The _Drosophilinæ_ are small, dull-coloured flies, the _larvæ_
of which feed on fungi, rotten fruit, and similar substances.
[Illustration: Fig. 152.--Hypoderma Bovis (Mag.)]
The last sub-family, namely, the _Agromyzinæ_, is very extensive. One
of the commonest species is _Phytomyza ilicis_, the _larva_ of which
forms large brown blotches on the leaves of the holly.
[Illustration: Fig. 153.--Diopsis Subfasciata (Mag.)]
_Family 35, Phoridæ._--The insects belonging to this family are
generally of small or moderate size. They are very active, and may be
observed on plants, and also sometimes sunning themselves on windows.