RHYNCHOTA. 
187 
(Labidura riparia), found somewhat rarely in England along the south coast, 
is nearly twice the size of the common species, and its forceps has a large tooth 
beyond the middle of its length. 
Order Rhynchota. 
The numerous insects included in this order exhibit great differences in their 
external form, and wdiile some, such as the Flatince, rival the butterflies and moths 
in the beauty and delicacy of their colours, others are amongst the most loath¬ 
some of creatures. But whatever be their form or colour, all ao-ree in two 
essential characters, the first consisting in the fact that their development takes 
place without a complete metamorphosis; and the second that all have the 
mouth taking the form of a beak, or rostrum, adapted for piercing and sucking. 
The beak consists chiefly of the lower lip (labium), which is long and narrow, 
composed of three or four joints, and grooved along the whole length of its upper 
or anterior surface. This groove forms a sort of sheath, in which are lodged four 
long slender blades, corresponding to the mandibles and maxillse of other insects, 
but here transformed into piercing organs. All these parts are covered at the 
base in front by the narrow and slightly elongated upper lip (labrum). From 
the structure of their mouth, which is fitted only for the reception of liquid nutri¬ 
ment, it is easy to infer that these insects live by piercing tissues of plants and 
animals, and extracting the juices. The larvm differ little from the adults except 
in size, the absence of wings, and their usually shorter and more slender antennse. 
In many, however, the females are without wings at all stages; and in some 
cases both sexes are thus unprovided. When wings are present, they may be all 
of similar texture, or the front-pair may be somewhat stiffer and less membranous 
than the hinder. Wings of both these kinds are found in the section Homoptera. 
In other cases, while the hind-wings are entirely membranous, the front-pair are 
stiff and horny for some distance from their base, and thin and membranous 
towards their extremities. Such wings, which characterise the section Heterop- 
tera, are known as hemi-elytra. Over eighteen thousand species are already 
known. Fossil remains of the order are found in strata of the Jurassic epoch, 
and are tolerably abundant in amber and other beds of Tertiary age. 
All the Heteroptera, no matter how different they may be in external form 
or mode of life, are termed bugs, although this name was originally applied only 
to the bed-bug and a few closely-allied species. Most are winged insects, in 
which the fore-wings known as hemi-elytra, or simply as elytra, always have 
the form described above. Their antennae are either short and inconspicuous, 
as in the water-bugs, or distinctly visible as in the land-bugs, and are generally 
composed of a small number of joints. As a rule they have tw T o compound eyes, 
and often two or three ocelli. The first segment of the thorax is usually large, 
with the head sunk deeply into it. The abdomen generally has an oval flattened 
form, and the legs are mostiy slender. Witli few exceptions bugs are characterised 
by a peculiar and somewhat unpleasant odour, which arises from a liquid secreted 
by special glands placed in the front part of the abdomen, and opening to the 
exterior by means of two small ostioles on the ventral surface of the metathorax. 
