106 
zooLOor. 
spines, the middle lobe unarmed and spatula-shaped, while the outer 
forms a five-jointed feeler called the maxillary palpus. The maxillae 
are accessory jaws, and probably serve to hold and arrange the food 
to be ground by the true jaws. The floor of the mouth is formed by 
the labium (Figs. 127 and 128), which in reality is composed of the 
two second maxillae, grown together in the middle, the two halves 
being drawn separately in Fig. 127. 
Within the mouth, and situated upon the labium, is the tongue 
{lingua\ which is a large, membranous, partly hollow expansion of 
the base of the labrum; it resembles a beech-nut in shape, being 
slightly keeled above, and covered with fine, stiff hairs, which, when 
magnified, are seen to be long, rough, chitinous spines, with one or 
two slight points or tubercles on the side. 
The internal anatomy may be studied by removing the dorsal wall 
of the body with fine scissors, and also by hardening the insect sev- 
eral days in alcohol and cutting it in two longitudinally by a sharp 
scalpel. 
The mop)hagus (Fig. 130, m) is short and curved, continuous with 
the roof of the mouth. The two salivary glands consist eacii of a 
bunch of follicles, emptying by a common duct into the floor of the 
mouth. 
The oesophagus is succeeded by the crop (ingluvies). It is in the 
crop that the ''molasses" thrown out by the locust originates. 
The proventriculus is very small in the locust, easily overlooked in 
dissection, while in the green grasshoppers it is rather large, and 
armed with sharp teeth. The true or chyle-stomach is about one 
half as thick as the crop. 
From the anterior end arise six large pockets (gastric mca), which 
arise from the true chyle-stomach, and probably serve to present a 
larger surface from which the chyle may escape into the body-cavity 
and mix with the blood, there being in insects no lacteal vessels or 
lymphatic system. 
The stomach ends in a slight constriction, at which point the 
urinary tubes (Fig. 130, ur) arise. These are arranged in ten groups 
of about fifteen tubes, so that there are about one hundred and fifty 
long, fine tubes in all. The stomach is succeeded by the ileum, 
colon, and rectum (Figs. 130, 131). 
The nervous system of the locust, as of other insects, consists of 
a series of swellings or nerve-centres, or so-called brains (ganglia), 
which are connected by two cords (commissures), the two cords in 
certain parts of the body in some insects united into one. There are 
in the locust ten ganglia, two in the head, three in the thorax, and 
five in the abdomen. The first ganglion is rather larger than the 
others, and is called the brain." The brain rests upon the oesoph- 
