320 ZOOLOGY. 
maxille, and labium. The mandibular nerves project for- 
ward and arise from the anterior part of the ganglion, near 
the origin of the supra-csophageal commissures, while the 
maxillary and labial nerves are directed downward into 
those organs. 
The sympathetic ganglia are three in number ; one situ- 
ated just behind the supra-csophageal ganglion (Fig. 273, 
as), resting on the esophagus, and two others situated each 
side of the crop, low down. Hach of 
the two posterior ganglia is supplied 
a by a nerve from the anterior ganglion. 
Two nerves pass under the crop con- 
necting the posterior ganglia, and 
from each posterior ganglion a nerve 
is sent backward to the end of the 
proventriculus. <A pair of nerves pass 
under the cesophagus from each side 
of the anterior sympathetic ganglion, 
and another pair pass downward to a 
round white body, whose nature is 
unknown (Fig. 273, u). 
Fig. 280 represents an enlarged 
view of the brain and sympathetic 
Fig, 280.—Supra-cesopha- nerve ofa moth. The heart isa long 
geal ganglion and visceral (Or tube lying in the abdomen, dilating 
sympathetic) nervous system 
Y the ilk-worm moth (Bom- ; : 
bye Saori, aie, BIGTEA(EBO- at six places along its course, and 
phag 
eal ganglion (“brain”); ending in a conical point near the 
@, antennary nerve ; 0, optic 
nerve; 7, azygos trankof the end of the abdomen; it is held in 
Te coata* prialo rom. ths place by fine muscular bands. 
aprirod perve with ts gang All insects breathe by means of a 
‘After eh Geren: complicated system of air-tubes rami- 
ial fying throughout the body, the air 
entering through a row of spiracles, or air-holes, or breath- 
ing-holes (stigmata), in the sides of the body. There are in 
locusts two pairs of thoracic and eight pairs of abdominal 
spiracles. he first thoracic pair (Fig. 281) is situated on 
the membrane connecting the prothorax and mesothorax, 
and is covered by the hinder edge of the protergum (usually 
called prothorax). The second spiracle is situated on the 
