532 Prof. E. A. Minchin. Report on the [Aug. 17, 
or to state how far Glossina differs from other Diptera as regards internal 
structure. I shall content myself, therefore, with describing the facts 
observed by me in a purely objective manner. 
In the following description I shall employ the term waist for the narrow 
peduncle connecting the thorax and abdomen, and neck for the still narrower 
connection between head and thorax. 
1. The Nervous System of Glossina, as of other Diptera, is concentrated into 
two masses, one situated in the head, the other in the thorax. 
The brain (fig. 1) consists of the two large cerebral ganglia (S. O. G.) 
giving off laterally the still larger optic lobes (Op. /.), from which arise the 
optic nerves. The dissection of the brain and its nerves is rendered some- 
what difficult by the large air-sacs, dilatations of the tracheal system, 
contained in the head. From the anterior side of the cerebral ganglia various 
nerves are given off: first,a median nerve of moderate size to the three ocelli 
(oc. n.), arising from the furrow between the two cerebral ganglia, and 
apparently swelling out into a small ganglion; secondly, a pair of nerves to 
the antenne, arising about half-way down the front of the brain on each side; 
thirdly, a pair of small nerves which innervate the muscles of the pharynx, 
arising near the base of the brain; and lastly, a pair of nerves to the 
proboscis, which arise from the base of the brain, run forward ventrally 
to the pharynx, giving off nerves at this point to the muscles of the 
proboscis, and finally enter the bulb of the proboscis, to be distributed to the 
mouth-parts (fig. 5, 7. p.). 
From the posterior surface of the brain, near its base, the two stout 
connectives (fig. 1, Cn.) arise, and pass down on each side of the greatly 
narrowed cesophagus, after which they unite almost immediately to form a 
single broad band of nerve-tissue, which runs back through the neck to join 
the thoracic ganglion-complex. From this connective band, as it may be 
termed, there arises, immediately after it enters the thorax, a slender pair of 
nerves, which form a delicate plexus with the first pair of prothoracic nerves 
arising a short way behind them (fig. 1, Cn. n.). 
The connective band often appears distinctly double at its junction 
posteriorly with the thoracic ganglion-mass, which lies immediately ventral 
to the stomach, the anterior end of the former being a short distance behind 
that of the latter. It is a mass of considerable thickness in the dorsoventral 
direction, and appears more or less pear-shaped in a dorsal view, but seen 
from the ventral side its anterior end appears truncated. When stained, 
cleared, and mounted in Canada balsam, it is seen distinctly to be composed 
of three pairs of large ganglia united together, corresponding to the three 
segments of the thorax, behind which a small mass of ganglion-cells, 
