1929 ] 
Tracheal System of Pyrausta nubilalis 
345 
ditions of the tracheae seem to be so constant in representa- 
tives of this order (Lepidoptera) which have been studied 
that it would seem very improbable that there should be 
such a great difference between two members of the same 
genus as Enderlein’s figure would indicate.” 
Peterson’s figure was drawn from a ventral dissection, 
and in the case of Pyrausta nubilalis , the tracheal supply to 
the prothoracic leg cannot be properly seen from this as- 
pect, for the spreading of the insect breaks the transverse 
trachea 2-a, and the leg then appears to have either but 
one branch to it, or if two branches are seen to enter the 
leg, the transverse character of 2-a cannot be seen. With 
regard to the meso- and metathoracic legs, the least that 
can be said is that in the European corn borer their supply 
is very different from this supply as shown by Peterson in 
the tomato-worm. 
The tracheal supply to the proleg of the third abdominal 
segment is shown in Figure 27. It is a branch running 
almost directly downward from, and at right angles to, the 
posterior branch of the trachea supplying the ganglion 
of the segment. The proleg trachea divides shortly after 
leaving the main branch, and two branches enter the leg. 
The anal proleg is supplied by a long branch running back- 
ward from near the eighth abdominal spiracle in a manner 
suggestive of the branch running forward, in the head, to 
the mandible. (Fig. 28). 
The tracheal supply to the wing-buds has been described, 
and is apparent in the figure (Fig. 26). 
Trachese to the Alimentary Tract, Fat Bodies, Silk Glands 
and Malpighian Tubules 
The tracheae to the alimentary tract, fat bodies, silk glands 
and Malpighian tubules must be treated largely under the 
same heading, for they are all branches from the same 
stems. 
A large branch arises from the main tracheal trunk near 
its junction with the spiracular trachea. This branch runs 
across the body cavity and splits into branches, most of 
which supply the alimentary tract. These branches from 
