The _Planipennia_ contains the most typical forms of the _Neuroptera_.
This sub-order is subdivided into six families, four only of which
contain representatives in the British Isles. They are most abundant
in the tropical parts of the world, where also the most handsome and
curious forms occur.
[Illustration: Fig. 43.--Myrmeleon Formicarius.]
_Family 1, Myrmeleontidæ._--The Ant Lions are the most familiar and
important members of this family. The common Ant Lion (_Myrmeleon
europæus_), which is abundant in sandy places in the south of Europe,
is a slender and elegant creature, with large finely reticulated rings.
The _larva_, to which the name of "Ant Lion" properly belongs, is of a
stout form and a greyish-yellow colour, covered with warty processes
and with hairs. Its food consists of ants and other small insects,
which it captures by a singularly ingenious arrangement, namely, by
means of a funnel-shaped pitfall which it constructs in the sand, and
at the bottom of which it lies. When any unfortunate insect ventures
too near, the Ant Lion sends up a shower of sand, and the victim in
its consternation falls down the pit, where it is speedily seized and
devoured.
Other species of ant lions are known to occur on the continent of
Europe, but none hitherto have been discovered to inhabit this country.
[Illustration: Fig. 44.--Myrmeleon Larva.]
[Illustration: Fig. 45.--Nemoptera Coa.]
_Family 2, Hemerobiidæ._--The second sub-family contains the Lacewing
Flies, many representatives of which occur in the British Isles. They
are among the most elegant and beautiful of the _Neuroptera_.
The Golden-eyed Fly (_Chrysopa vulgaris_) is a very abundant and
well-known example, but notwithstanding its great beauty it is capable
of emitting a very disagreeable odour when handled. This is a delicate
green insect with a body half an inch long, and which may be seen
almost everywhere on warm summer evenings, flying slowly about from
tree to tree. The eggs, which are little round or oval bodies like
small pearls, are deposited by the female in groups upon the leaves of
plants and trees. The _larva_ when fullfed is about half an inch in
length. The food consists of plant lice and aphides, and it is thus a
very beneficial creature, and should be encouraged by every gardener.
The _pupa_ of this insect is enclosed in a cocoon. Between thirty and
forty species of lacewing flies are known to occur in our own country.
[Illustration: Fig. 46.--Chrysopa Septempunctata.]
[Illustration: Fig. 47.--Mantis Pagana.]
_Family 3, Mantispidæ._--This family contains only one genus--viz.,
_Mantispa_, or the Mantis Flies. A single species, _Mantispa pagana_,
is common in southern Europe, but does not occur in the British Isles.
_Family 4, Sialidæ._--In the fourth family of the _Planipennia_ the
_larvæ_ are aquatic in their habits with very few exceptions. The
_pupa_ is not enclosed in a cocoon as it is in the _Hemerobiidæ_. The
single common British species (_Sialis lutaria_) is a blackish-brown
insect, rather more than half an inch in length. It is well known to
anglers, and may be found abundantly in the spring and early part of
the summer upon walls and palings in the neighbourhood of water, and
upon the stems and leaves of grasses and other plants growing in the
water or upon its bank.
In repose the wings of this insect, as in the _Hemerolicidæ_, are laid
over the back. They are sluggish creatures, and do not readily take to
flight.
_Family 5, Raphiidæ._--This family contains the curious group of
insects called "Snake Flies" or "Camel Flies," which are included by
some entomologists in the previous family. They have characteristics,
however, which entitle them to be placed apart. They have a rather
large head, which is attached to a greatly elongated prothorax by a
thinnish neck, so that the head has considerable freedom of motion. The
species are not numerous, four kinds only occurring in Britain. The
_larvæ_ reside under the bark of trees, where they feed upon minute
insects. The commonest species is probably _Raphidia megacephala_.
[Illustration: Fig. 48.--Raphidia Ophiopsis (Mag.)]
[Illustration: Fig. 49.--Panorpa Communis.]
_Family 6, Panorpidæ._--The _Panorpidæ_, or Scorpion Flies, are
very curious creatures, characterised above all things by the
perpendicularly placed and greatly elongated head.
The _larvæ_, so far as they are known, live in the earth, and are like
caterpillars in their general form.
Five species occur in this country, the best known being _Panorpa
communis_, which may be met with almost everywhere about hedge banks
and in lanes. It is about half an inch long. The wings are transparent,
with dark brown spots, which are more or less confluent.
Another species, _Boreus hiemalis_, which possesses no wings, is found
on the ground among leaves in the winter time. It does not exceed
one-sixth of an inch in length, and is of a metallic-green colour.
[Illustration: Fig. 50.--Bittacus Tipularius.]
[Illustration: Fig. 51.--Boreus Hiemalis (Mag.)]