_Lepidoptera_, or butterflies and moths; _Diptera_ or flies, gnats, etc.;
_Hemiptera_, or bugs, including the plant-lice, etc.
These divisions, however, have not been found to be very satisfactory,
although very simple when dealing only with the perfect insect stage. In
the first place, being framed on this stage only, they are not always
applicable to the earlier phases of the insect's life--for instance,
although a butterfly or moth has a sucking proboscis, their caterpillars
have strong biting jaws, as any gardener well knows. Also bees, wasps,
etc., rather upset the arrangement, as they have not only a sucking mouth
but also strong biting jaws.
This system of classification has therefore been discarded by most
entomologists in favour of that based on the difference between those
insects which pass through the distinctive stages of caterpillar and
chrysalis on the one hand, and those which emerge from the egg as
diminutive likenesses of their parents on the other. In this arrangement,
the _Coleoptera_, _Hymenoptera_, _Lepidoptera_, _Diptera_ and _Neuroptera_,
fall into the {130} first division, or _Heteromorphae_ as they are called;
and the _Hemiptera_ and _Orthoptera_ into the second or _Homomorphae_. The
dragonflies are the only slightly discordant elements in this arrangement,
as, although their larvae have six legs and walk about under the water and
never assume an actual chrysalis condition, still they can hardly be said
to resemble their gorgeously coloured parents which fly about so
majestically over our ponds, etc.; still this is only one of the many cases
which show that nature cannot be held down by any of the arbitrary rules we
make for her classification.
The _Hymenoptera_ are therefore characterized and distinguished from other
insects by having both a biting and sucking mouth, four clear wings, and by
passing through the distinctive liveries of caterpillar or grub, and
chrysalis or nymph. It is with this order only with which we have been
dealing. To distinguish the aculeate section from the many other forms of
the _Hymenoptera_ is too complex a task to undertake here, but the presence
of a narrow waist between the thorax and the body, the number of joints in
the antennae never exceeding thirteen in {131} the male, twelve in the
female, and the presence of a sting capable of ejecting poison in this
latter sex, are the most prominent features by which the aculeates may be
recognized.
* * * * *
{132}