184 General Notes. ; [Feb. 
notice of Forel, incorrectly associated with the nerve-end appa- 
ratus found by Hicks in other insects. This manifold nature of 
the antennal organs has by the last investigator, Hauser (22), 
from thorough studies of the nerve-elements belonging to them, 
been not simplified but rendered more complicated. According 
to this naturalist we may distinguish the following forms which 
the olfactory organs may assume: I. Pale, tooth-like chitinous 
hairs on the outer surface of the antennz, which are perforated at 
the end; nothing is known as to the relation of the nerve passing 
into it (Chrysopa, Anophthalmus). 2. In pit-like depressions of 
the antenne arise nerve-rods (without a chitinous case) which 
These pits are either szzf/e, viz., with only an “olfactory rod 
(Tabanus and other Diptera, Vanessa), or compound (Muscide 
and most other Diptera, and Philonthus). It seems important 
that these pits are partly opez (in the above-named groups of in- 
sects), and partly closed and covered with a thin membrane, under 
whose concavity the olfactory rods end (Orthoptera, Melolontha, 
and other lamellicorns). 3. Short, thick pits sunken slightly 
into the surface of the antennz, and over this a chitinous peg 
perforated at the end, in whose base, from the interior, projects a 
very singular nerve-peg, which is situated over an olfactory gan 
glion-cell, and provided with a slender crown of litle rods, and 
flanked on each side by a flagellum-cell | (Hymenoptera). 4. 
Round or crevice-like pits covered over by a perforated chitinous _ 
membrane with nerve-rods like those in 3, but in place of the 
flagellum-cell with “membrane-forming”’ cells Spread before it. 
Hauser finally mentions further differences in the ganglion-cells 
sent out into the nerve-end apparatus. These exhibit in Diptera 
and Melolontha only one nucleus, in Hymenoptera a single very 
large one (with many nucleoli) and three small ones, in Vanessa 
six, in Orthoptera a very large number of nuclei, etc. We add 
beside all these different forms also the Forelian flasks (“ micro- 
scopical stethoscopes” of Lubbock) not known to Hauser, and 
the champagne-cork organ in ants; thus we have in fact a very 
great variety, so that it seems difficult to understand how Hauser 
could aamen ascribe a common function to all these nerve- 
end appara’ 
As the ans result of my researches I may state that the great 
variety of antennal structures previously described may be referred 
to a single common fundamental type of a more or less developed 
free or sunken hair-like body which stands in connection by means 
of a wide pore-canal walle a many-nucleated ganglion-cell.* The 
latter sends mice a relatively n nerve-fibre (axial cord) through 
o Vi oop thie  stracture might’ more more correctly be considered as a lion with 
: Humerus cells, ee structure of the nerve: ae 
OH E sg arom gl -a ca 
