1912] Anatomy of Tomato-worm Larva 253 
bladder, there is a common duct, which splits immediately 
and gives rise to two branches; one continues cephalad on the 
ventral side (v. m. t.), while the other passes dorsad and divides 
into two branches (d. m. t.), both of which proceed cephalad 
along the dorso-lateral part of the ventriculus. Tracing a 
ventral Malphigian tubule, we find that it extends cephalad in a 
nearly straight line, adjacent to the ventro-lateral portion of 
the ventriculus to the second abdominal segment. At this 
point it turns abruptly back and continues caudad and parallel 
with itself until it reaches approximately the seventh abdominal 
segment, where it becomes very convoluted and soon loses itself 
in the mass of convoluted, terminal, Malphigian tubules and 
adipose tissue. The pairs of dorsal tubules proceed cephalad 
and parallel into the second and third abdominal segments... 
The mesal tubule of the pair within the third abdominal seg- 
ment, turns mesad and caudad, while the lateral tubule turns 
laterad and caudad within the second abdominal segment. 
After turning, both tubules proceed caudad and parallel with 
their cephalad-extending portion until they reach the sixth 
abdominal segment, where they turn laterad and continue into 
the seventh abdominal segment soon to become highly convo- 
luted and intertwined with the ventral, terminal tubules and 
adipose tissue. The tubules are easily detected not only from 
their position, but from their form. They appear like long, 
white, knotted strings. The proximal portion of a tubule is 
more or less flattened and consists of scattered, white, globular 
nodules. Asa tubule proceeds distad, the nodules become more 
frequent until finally at the terminal part of a tubule, as it 
enters the seventh abdominal segment, the tubule consists of a 
series of closely packed, irregularly arranged nodules. It was 
impossible to determine the termination of a tubule on account 
of the intertwining of the tubules, their delicate consistence, 
and the ever present adipose tissue. 
SILK GLANDS. 
Running along each side of the lateral portions of the ven- 
triculus (Fig. 7, sg) and imbedded in the adipose tissue of the 
lateral body wall, are two opaque, smooth, yellowish-white 
cords. These two cords are the silk glands. They extend 
from the base of the spinneret on the labium into the seventh 
abdominal segment. The right and left silk glands of this larva 
