346 
Psyche 
[December 
the main trunk are found arising from near the first to the 
eighth abdominal spiracles. None rise in the thorax. 
Alimentary Tract 
The trachea to the alimentary tract arising from near the 
first abdominal spiracle is different in origin from that 
observed in the other tracheae supplying the tract. It does 
not arise directly from the main trachea, but is the first 
branch from the trachea that also gives rise to the pos- 
terior stem of the metathoracic leg tracheae. The other 
tracheae to the alimentary tract arise directly from the 
main longitudinal trunk. 
The figure illustrating the tracheae to the alimentary 
tract, (Fig. 29), shows the trachea arising near the first 
abdominal spiracle, and supplying that part of the tract 
just behind the oesophagus. In the figure this portion of the 
alimentary tract is shown much distended. As a rule the 
alimentary tract behind the oesophagus, from which it is 
distinctly separated, is of more or less uniform diameter 
throughout its length. This particular specimen is chosen 
for illustration, however, because the enlargement spreads 
the tracheae, making their distribution easier to trace. 
The supplying trachea arises as a branch of a trachea 
arising from the longitudinal trachea near to the spiracular 
trachea. The supplying trachea runs forward and upward, 
breaking into four main branches, one running forward 
and one running backward on the dorsal surface of the 
tract, and one running forward and one running backward 
on the ventral surface. These, with their branches, enclose 
the tract in a sort of basket of tracheae. 
This same arrangement appears in the tracheae to the 
alimentary tract behind the first abdominal segment. 
The oesophagus is poorly supplied with tracheae. Some- 
times a very small branch will enter it, but there is no 
basket-work of tracheae around it, and no main tracheal 
branch to it. 
Fat Bodies 
The fat bodies are large masses of white material dis- 
tributed within the body cavity somewhat as follows : A 
