260 Annals Entomological Society of America [Vol. V, 
Median and Transverse Nerves—The median nerve (m) 
arises from the commissure at the cephalic end of this inverted 
V-shaped split and extends caudad for a short distance. At its 
caudal end near the ganglion, it forks and gives rise to two 
transverse nerves (¢. 1.), that extend in opposite lateral direc- 
tions and more or less parallel with the lateral nerves. In the 
short distance in which the transverse and lateral nerves are 
parallel, the transverse nerves give rise to a web of nerve fibres 
(px), which connect with the lateral nerves and the ganglion. 
Beyond this web or plexus, the transverse nerves diverge from 
the lateral nerves in a cephalo-lateral direction. 
Ganglia Seventh Abdominal Segment. (Fig. 14, A. 7 and 8 g). 
—Within the seventh abdominal segment, is a double ganglion, 
or rather two ganglia, but no visible commissure connects the 
two because of the close approximation of the ganglia. This 
modification brings about a change in the nerves. 
Seventh Abdominal Ganglion.—The seventh abdominal gan- 
glion is comparable to the ganglia of the first six abdominal 
segments. It gives rise to nerves arranged in the same manner 
and does not need further description. 
Eighth Abdominal Ganglion.—The elimination of the com- 
missure between the seventh and eighth ganglia has not only 
brought the ganglia together but has lengthened as well as 
changed the place of origin of the nerves from the ganglion. 
Lateral Nerves——The comparatively large lateral nerves (/) 
arise not from the lateral margin of the ganglion but from its 
dorso-caudal end and extend with a slight divergence far into 
the eighth abdominal segment before branching. 
Ventral Nerves.—Ventrad and slightly laterad of the lateral 
nerves, there arises a small pair of ventral nerves (v), which also 
extend into the eighth abdominal segment before branching. 
Adjacent to these ventral nerves the accompanying trachee, 
which resemble nerves closely enter the ganglion. The ventral 
trachea of the eighth abdominal segment, however, still exists 
in its normal position within the eighth segment. This elongates 
to a great extent the pair of trachez that arise from it to supply 
the eighth abdominal ganglion. 
Ventral Sympathetic System (Fig. 14, m. and ¢t. n.).—The 
fusing of the seventh and eighth abdominal ganglia causes the 
sympathetic system apparently to arise from the dorso-caudal 
end of the seventh abdominal ganglion. 
