10 
INTRODUCTION. 
In the Bugs and their allies, which belong to the 
order Rliyncota , we have another form of suctorial 
mouth; here the labial palpi coalesce and form a jointed 
beak or rostrum , which is a tube split down the front, 
and enclosing two pairs of bristle-like organs, which are 
really greatly altered forms of the mandibles and 
maxilke; by means of these sharp and fine needles the 
Rhyncota pierce the tissues of animals or plants, and 
feed on their juices. 
In the Fly kind the ligula is developed into a broad 
fleshy organ or proboscis—whose form must be familiar 
to the most careless observer—through which the insect 
sucks up its food. In the Dlptera generally, as in the 
common gnat, the labium consists of a long cylindrical 
organ with a round top at the extremity ; along the 
upper surface of the labium runs a groove which sheathes 
the other organs of the mouth, viz., the mandibles, 
maxillae, ligula, where it exists, and the labium ; all of 
which are delicate cutting lancets, by means of which 
the insect pierces its victim and sucks out the juices. 
When you see this formidable array of miniature 
lancets and javelins, you will not wonder at the rapidity 
with which a gnat punctures your skin, and how im¬ 
mediately you feel the wound. 
We now come to the second division of an Insect’s 
body, which as we have seen consists of three parts, 
though from frequent amalgamation these segments are 
not always distinguishable ; the} r constitute the thorax, 
and bear the organs of motion, almost always in insects 
six legs, and generally four wings; each leg is either firmly 
attached to, or articulated with the thorax by a quasi 
ball and socket joint, at the first joint, called the coxa 
