1912] Anatomy of Tomato-worm Larva 263 
The commissure extending between these two ganglia fail to 
unite before entering the caudal end of the subcesophageal 
ganglia; consequently the two ganglia are connected by two 
distinct parallel strands. 
Lateral Nerves——The lateral nerves (/) are the two branches 
which arise from the cephalic part of the lateral margins of the 
ganglion. These nerves soon divide into many small branches 
and innervate the lateral areas of the prothorax. 
Ventral Nerves——The ventral nerves (v) project from the 
caudo-lateral margin and are accompanied by the usual pair of 
trachee. In this ganglion however, the ventral nerve of each 
side is not single but is composed of two small branches. 
Ventral Sympathetic System.—With the prothoracic gan- 
glion, the customary median and transverse nerves are wanting 
but the following new arrangement exists :— 
Subconnective Nerve (Fig. 17, T. 1g).—Dorsad and cephalad 
of the prothoracic ganglion, the large subconnective nerves 
(sn) exist, which cross the commissure. Within the region 
adjacent to the ganglion, a plexus or web of nerves (px) extends 
between the subconnective nerve, the ganglion, and the prox- 
imal ends of the lateral nerves. 
GANGLIA OF THE HEapD (Fig. 17, H. 1g and H. 2g, Fig. 18).— 
In the alimentary tract as it extends to the mouth by means of 
the pharynx, there is to be noted a distinct flexure in the head. 
The two head-ganglia are located slightly distad of this flexure. 
The corresponding flexure in the nervous system is located 
between the subcesophageal and prothoracic ganglia. The two 
head-ganglia rest on the pharynx but on opposite sides (Fig. 18). 
The more distal ganglion, the supracesophageal (sp), is cephalad 
of the pharynx and entad of the front of the head capsule. The 
subcesophageal ganglion (sz) is caudad of the pharynx and 
connected to the supracesophageal by means of two commis- 
sures, which together with the two ganglia form a complete 
ring about the pharynx. 
Suboesophageal Ganglion (Fig. 17 and 18, sw).—The sub- 
cesophageal ganglion is located caudad of the pharynx and ina 
plane ventrad of the supracesophageal. It gives rise to the 
following nerves :— 
Crura Cerebrt.—The crura cerebri (c. c.) arise from the 
cephalo-ventral portion of the lateral margin of the suboeso- 
phageal ganglion very close to the pharynx. This pair of large 
