L. Harrison 
119 
that two long branches run forwards from the prothoracic commissure 
into the head, extending beyond the brain. Gliricola also has two head 
commissures. 
All parts of the body are profusely supplied with tracheal branches, 
which ramify through the fat-body and muscles, are thickly applied to 
the alimentary canal throughout its length, and to the internal genitalia, 
and which are especially abundant about the nerve ganglia. I cannot 
find in sections any trace of tracheal tubes actually entering into the 
ganglia, but they are closely and thickly applied to the whole surface. 
Fig. 21 is a camera drawing of the ventral surface of the metathoracic 
Fig. 21. Ventral view of metathoracic ganglion of Ooniodes piageti, to show tracheal 
supply. 
ganglion of Goniodes piageti, showing the neural commissure lying 
across it, and the extraordinary number of branches applied to the 
surface. These are not so numerous on the other ganglia, so I conclude 
that the metabolism must be more active here, as the ganglion innervates 
about three-quarters of the body, while the remaining quarter has four 
ganglia at its service. 
The minute structure of the tracheal tubes agrees with that of insects 
in general. Each consists of a chitinous lining secreted by a cellular 
layer which is continuous with the reflected hypodermis. The nuclei 
of this layer can be seen (Fig. 18, Tr) easily enough, but I cannot make 
