INSECTS. 
166 
larva again lies in wait. If by chance the victim should escape the first onslaught, 
and endeavour to scramble up the sides of the pit, its attempt is soon frustrated, for 
the ant-lion throws up sand with its head, causing the victim to tumble once more to 
the bottom. 
The lace-wings flies (Hemerobiidce and Chrysopidce), are smaller and more 
delicate insects than the ant-lions, and have setiform antennae. The golden¬ 
eyed fly (Chrysopa vulgaris), figured on p. 165, may be taken as a typical species. 
It is slender, with long and richly-veined wings of a tender green colour, as 
is also the body. Its antennae are long and tapering, and its prominent eyes 
shine like hemispheres of gold. The larvae of the lace-wings are not unlike the 
ant-lion, although somewhat longer and narrower in proportion to the size of 
their bodies, and less hairy. Their mandibles, moreover, have no teeth on the 
inner side. In their carnivorous habits they resemble ant-lions, but instead of 
making pits and remaining stationary they rove about in search of their prey, 
which consists of the different kinds of green-fly and plant-lice. 
Order Orthoptera. 
This order being taken to include, not only the true Orthoptera, but various 
other groups formerly placed in the Neuroptera, and hence known as Pseudoneurop- 
tera, it is necessary in defining the group to mention only such characters as are 
common to the whole of these insects. None of the members of the group undergo 
a distinct metamorphosis; the development from the larval to the adult condition 
taking place by a succession of changes, and the perfect insects being distinguishable 
from advanced larvae by little more than the possession of complete wings. The 
wings are, however, in some cases confined to one sex, while in others they are 
altogether wanting in both sexes. The mouth-organs, when not reduced to 
a functionless condition, are adapted to biting; the lower lip (labium) is nearly 
always divided in the middle at its free end, and each of the two halves often sub¬ 
divided into a pair of lobes. On the floor of the mouth, concealed by the labium, 
there is, as a rule, a membranous or more or less horny structure, known as the 
tongue (lingua), or hypopharynx, which is free from the labium in its anterior part. 
Though poor in the number of species, as compared with some other orders, the 
Orthoptera contain many of the most interesting forms of insect life; some, like the 
leaf and stick-insects, remarkable for their size and the variety of their protective 
disguises, others, as the white-ants, for the wonderful development of their social 
habits. The day-flies are noted for the shortness of their lives, the dragon-flies for 
their beauty; while many other forms are well known from some particular feature 
or habit. In past epochs of the earth’s history Orthoptera were well represented, 
their remains being found in rocks of various ages extending back to Palaeozoic 
times. The oldest reputed insect is known by the impression of an orthopterous 
wing ( Palceoblattina ), from the Silurian sandstone of Calvados in France. There 
is some doubt as to which group of the order the insect belonged, and even as to 
whether the impression owed its origin to an insect at all. However this may 
be, traces of undoubted Orthoptera, as well as of Neuroptera, are met with in rocks 
of Devonian and Carboniferous ages. The Orthoptera of the latter period included 
