INCLUDING THE BEES, WASPS, ANTS, ICHNEUMON FLIES, SAW FLIES, GALL
FLIES, AND THEIR ALLIES.
[Illustration: Fig. 5.--Cryptus Formosus.]
The _Hymenoptera_ belongs to one of the most interesting and extensive
orders of insects. The structure and habits of the different species
which it includes are very various. Their marvellous instincts have
excited the admiration and wonderment of the philosophers of all ages.
They are, indeed, by far the most intelligent of insects, being greatly
in advance of any other group known to exist. The _Hymenoptera_ are
mandibulate insects, their mouths being formed for biting, and they
undergo complete metamorphoses. Perhaps the most striking external
distinctive character is to be found in the structure of the wings,
both pairs of which are membranous; and another peculiarity of equal
importance is the condition of the prothorax, which is reduced to very
small dimensions. In the majority of the _Hymenoptera_ the females are
provided with stings, which serve many purposes, independently of
weapons of defence. Many families, however, do not possess stings.
Many of the _Hymenoptera_ feed on plants and trees, but probably the
greater number are parasitic on other insects.
[Illustration: Fig. 6.--Pimpla Turionellæ (Mag.)]
This order includes the bees, wasps, ants, saw flies, gall flies,
ichneumon flies, and many other familiar insects.
The following will show the principal characteristics of each group
into which the order has been divided.
_Tribe 1, Aculeata._--Generally social insects, consisting of males,
females, and neuters. Ovipositor modified into a sting. _Larvæ_,
footless grubs.
_Tribe 2, Entomophaga._--Mostly parasitic on the eggs and larvæ of
other insects. Ovipositor used as a borer. _Larvæ_, footless grubs.
_Tribe 3, Phytophaga._--Principally vegetable feeders. Ovipositor used
as a borer. _Larvæ_ having six or more legs.