The principal character of the insects belonging to this tribe consists
in the adaptation of the hind legs to the purpose of leaping.
The males of most of the species possess the faculty of producing loud
chirping sounds, but the means by which this is effected vary in the
different families.
_Family 4, Achetidæ._--The most familiar British insect belonging to
this family is the common House Cricket (_Acheta domestica_). Living,
as it does, in the immediate vicinity of the fire, it seems to be
totally independent of the changes of the seasons, and may usually be
found of all ages at all periods of the year. Crickets are particularly
abundant in bakehouses, being extremely partial to warmth. The chirping
noise which they produce at night-time is sometimes almost deafening,
and it is really surprising from what a very long distance the sound
may be heard.
Their food consists of bread crumbs and scraps of meat and vegetables
which have been allowed to accumulate during the daytime. The best
way, therefore, to get rid of the insects is to take proper care in
clearing away all the refuse after meals, for if this were not there
the crickets could not subsist, and would soon quit the house. They
are, however, generally objected to only by weak-nerved people, and do
very little harm, if any whatever. It is a question whether they are
not very useful in acting as scavengers.
[Illustration: Fig. 70.--Hetrodes Pupa.]
[Illustration: Fig. 71.--Gryllotalpa Vulgaris.]
A nearly allied British species is the Field Cricket (_Acheta
campestris_), which is rather larger than the house cricket. It is
comparatively rare and local in this country, but abounds everywhere on
the Continent.
A third British species is the Wood Cricket (_Nemolicus sylvestris_),
which is considerably rarer than either of the preceding. It is found
abundantly among dead leaves in woods in France and other parts of the
Continent, but is very rarely found in England.
The Mole Cricket (_Gryllotalpa vulgaris_) is perhaps the most
interesting member of the family. It is a large, robust insect, about
an inch and a half in length and of a very dark brown colour. It is
remarkable for the peculiar shape of its front legs, which exactly
resemble those of the mole.
It burrows in loose soil, and, like the mole, it passes along close
beneath the surface of the ground, and often raises a small ridge as it
advances. It frequents gardens, especially near the banks of canals,
and is also fond of damp meadows and other localities in the vicinity
of water.
The eggs to the number of 200 or 300, are deposited in a chamber of
considerable dimensions, and enclosed in a sort of cocoon-like envelope.
The _larvæ_ when first hatched are white, and are said to be three
years in arriving at a state of maturity. The mole cricket is found
chiefly in the south of England.
[Illustration: Fig. 72.--Œcanthus Pellucens.]
_Family 5, Gryllidæ._--The most conspicuous insect belonging to this
family in Britain is known as the great Green Grasshopper (_Phasgonura
viridissima_), which measures nearly four inches in expanse of the
wing, and is therefore nearly as large as the migratory locust which
sometimes visits us.
The great green grasshopper is not, however, a very common insect in
this country, being principally confined to the south of the island.
Another European and British species, _Decticus verrucivorus_, is of
about the same length. It receives its name from the custom prevailing
among the Swedish peasants of making it bite their warts. This insect,
in common with many others of the same family, when at all roughly
handled, emits from the mouth a brownish fluid, which is said to
possess acrid qualities, and the introduction of this into the warts is
supposed to cause their disappearance.
[Illustration: Fig. 73.--Truxalis Nasuta.]
_Family 6, Locustidæ._--This family, which includes the grasshoppers
and true locusts, is easily distinguished from both the preceding
families by the character of the antennæ, which are comparatively
short.
The common English Grasshopper (_Rhammatocerus biguttulus_), whose song
must be familiar to every one who has walked through the fields during
the summer time, is produced by the friction of the hinder thighs
against the wing-cases.
The locusts have been celebrated from the dawn of history on account of
the terrible ravages which they have committed in various parts of the
world; and although many different species have made their appearance
in our own country at various times, the climate, fortunately, seems
unsuitable for them to live in, and they have, therefore, not been
known to breed here.
The Migratory Locust (_Ædipoda migratoria_) is perhaps the best known
in this country on account of its visits, many stray individuals of
which have visited us at different periods.
Locusts are known all the world over, in fact, nearly every country has
a species peculiar to itself. The most extraordinary accounts are on
record of the vastness of the swarms which every now and again invade
particular districts. They are said sometimes to absolutely darken the
sun.
[Illustration: Fig. 74.--Decticus Verrucivorus.]
[Illustration: Fig. 75.--Locusta Peregrina.]
They clear off everything from the surface of the ground as completely
as if the place had been visited by fire.
In many eastern countries locusts are relished as articles of food.
The distinctive character of the insects comprised in this group is
found in the structure of the wings. The anterior pair are of a horny
or leathery consistence, but always much shorter than the abdomen. The
hind wings, on the contrary, are of large size, and are composed of a
very delicate membrane. There is only one family.
[Illustration: Fig. 76.--Caloptenus Italicus.]