i PT General Notes. i [March, 
body to the anterior cortex of the brain with its abundant gan- 
gilion-cells.* i 
The simple eyes have biconvex lenses and rhabdites joined to 
nerve fibers, which run back to the infero-posterior region of the 
brain, and thence advance so as to enter the central body. The 
antennal nerves run straight back to the antennal lobes (a/), 
whence some fibers run forwards to the central region of the 
brain. 
The “central body” has been described by investigators as a 
fan-shaped organ. Packard, after Newton, described it as a half- 
moon-shaped body, concave backwards and separated by a net- 
work of fibers from the brain, and supposed it to consist of modi- 
fied,cells. In Psyllidz it is bean-shaped, consisting of granulated 
matter not at all isolated from the surrounding parts of the brain, 
but receiving fibers from and sending fibers to the other lobes, 
and is nothing more than a central commissural system, its cell- 
like elements being the cross-sections of fibrous masses. 
4 he mushroom-bodies, described by authors, are found in Psyl- 
lide only in a rudimentary form, being some thick masses of 
ganglion-cells in the upper anterior bor- 
der near the median line, whence bundles 
_ of fibers run backwards. : 
Taken as a whole the brain, with its 
connections with procephalic ganglion- 
masses, subcesophageal commissures 
and ventral nerve-cord, and various lobes 
in its own mass, is complex; and it !s 
scarcely possible to join sections made 
in different directions into a unity, SO aS 
to get its real structure. As a whole 
ganglion-cells. The insect-brain is, there- 
í fore, a projection-centrum, the uap? 
o ae _room-body being special. The most ım- 
a a Paneer at oF portant nerves entering the brain (as 
ae Ee from the eyes, antenne, limbs) cause 
-a swelling in its medulla, where the fibers are deflected so as tO 
_ change their course. ‘ 
= Digestive tract—The mandibles and first maxillze are developed 
_ 1S, J. Hickson (in Quarterly Journal of Microscopical Science, April, 1885) S€ 
the terms opticon, epiopticon and periopticon for three medullary masses belonging = 
. PA > Musca; representing respectively om, es, and a tract near oc of © Fig- 
r 
Prae i 
-ject is there given 
*Second report U, S. Entomol, Commission, 1878-9. The literature of the sub , 
i 
