PSYCHE. 
scription of a number of the latter is given, 
with good figures. Like Flégel, Newton 
was unable to find the connection of the in- 
ternal ‘‘ framework ” with other parts of the 
nervous system. 
Dr. E. Berger has a memoir,” which I 
have not been able to see, on the structure 
of the brain and retina in the arthropods. 
It is, however, noticed by Newton in the 
preceding paper, who says it ‘‘is largely 
occupied with the description of the retina 
and the structures to be found in the optic 
lobes of arthropods. It is extremely inter- 
esting to find that the peculiar oval bodies 
which Leydig figured from the optic lobe 
of Dytiscus, and were afterwards described 
and figured by me in the eye of the lobster 
are to be found in a more or less modified 
form in all the insects and crustacea de- 
scribed by Berger. The remarkable cross- 
ing of the nerve fibres between the retina 
and the lenticular bodies is seen not to be 
peculiar to the lobster. The brains of a 
number of insects are described, and in 
each of them the author seems to have 
found the homologues of the ‘ mushroom 
bodies,’ although in some, e. g., the diptera, 
they are very rudimentary.” 
Our fellow member, Dr. E. L. Mark, 
has described * the nervous system of 
Phylloxera, correcting Prof. Riley’s * de- 
scription. The most striking peculiarity 
is the want of that concentration found in 
most of the plant-lice, there being two in- 
stead of one, post-oral ganglionic masses, 
5) Arb. Inst. Wien, v. 1, p. 173. 
51 Psyche, v. 2, p. 201, Jan. 1879. 
52 Prof. Riley admits his error in this respect 
(Psyche, v. 2, p. 225). In the same note he com- 
bats Cornu’s opinion that the mechanical action of 
the puncture and the subsequent absorption of 
39 
the first of which is a flattened, rounded 
mass, connected by very stout and short 
commissures with the second, larger, heart- 
shaped ganglion, the point of which con- 
tinues into a median nerve which, shortly, 
bifurcates. A good figure of the parts is 
given. 
Mr. Jules Kiinckel emphasizes in a short 
note * the importance of the nervous sys- 
tem as a guide to classification of insects, 
and discusses the affinities of the different 
families of diptera on this basis, a matter 
with which we are not here concerned ; but 
the fact that five families — Stratiomyidae, 
Conopidae, Tabanidae, Syrphidae, and 
certain acalypterous Muscidae — show a 
decentralization of the nervous system in 
the adult is very interesting. In these cases 
the ganglia, which are separated in the 
embryo, in the larva approach and coa- 
lesce, only to be again separated while in 
the pupal stage. Of the other diptera, 
some groups show the usual centralizing 
tendency with the development of the in- 
sect, and in others the ganglia remain in 
the same condition through life. 
I have also a reference to a paper * by 
Mr. J. W. Slater on the nervous system, 
but I have not seen it. 
New methods of preparation have given 
great impetus to the study of the eye, and 
we find several papers to record besides 
the independent work of Grenacher, already 
alluded to. Mr. B. T. Lowne is the author 
of one * on the modifications of the simple 
liquid, can alone account for the development of 
Phylloxera, or other, galls. 
53 Comptes rend., v. 89, p. 491. 
54 The Entomologist, v. 12, p. 291. 
65 Phil. Trans., v. 169, p. 577. 
