268 Prof. L. C. Miall and Mr, T. H. Taylor on the 
hooks become broader and the hooks more numerous. 
Areole, devoid of hooks, and answering to the attachments 
of segmental muscles, are found in the bands (fig. 7). In 
the third stage the 8rd—6th bands are continuous dorsally. 
The tracheal network is richer, and the anterior and 
posterior spiracles are functional, their initial threads 
having been replaced by open extensions of the main 
trunks (tracheal extensions). 
The spiracles have already been described as they appear 
in the first larval stage. We go on to describe the 
spiracles of the last larval stage, and then notice those of 
ex 
Fie. 8. 
Anterior spiracles of larva of 3rd stage. ap, earring-like appendage with filament ; 
ex, tracheal extension ; fch, ‘‘felted chamber” ; p, pit; st, closed spiracle with cord 
(‘‘ Narbenstrang’’). (x 280.) 
the second larval stage, which are intermediate in structure 
between the earlier and later ones. 
In the third stage the anterior and posterior spiracles 
project from the surface of the body. The anterior 
spiracle (fig. 8) is a compound structure (“compound 
spiracle” of De Meijere*) consisting of a functional 
and a closed spiracle, both carried on a cuticular process of 
the skin, The internal part of the functional spiracle 
* Zool. Jahrb., vol. xv, pt. iv, p. 623 (1902). 
