ON ABDOMINAL SEGMENTS. 231 
but he gives no figure. In Fig. 8 I have represented 
the junction of the second and third abdominal seg- 
ments in Lasiws flavus, x 225, as shown in a longi- 
tudinal and vertical section. There are about ten‘ 
well-marked ribs (7), occupying a length of approxi- 
mately ;4, of an inch. Similar ridges also occur 
between the following segments. 
In connection with the sense of hearing I may 
mention another very interesting structure. In the 
year 1844, Von Siebold described! a remarkable organ 
which he had discovered in the tibize of the front legs 
of Gryllus, and which he considered to serve for the 
purpose of hearing. These organs have been also 
studied by Burmeister, Brunner, Hensen, Leydig, and 
others, and have recently been the subject of a mono- 
graph by Dr. V. Graber,? who commences his memoir 
by observing that they are organs of an entirely unique 
character, and that nothing corresponding to them 
Fig. 9. 
Tibia of Zasius flavus §%.x 75. 
occurs in any other insects, or indeed in any other 
Arthropods. 
' Ueber das Stimm. und Gehororgan der Orthopteren, Wieg- 
mann’s Art. f. Natur., 1844. 
2 Die Tympanalen Sinnesapparate der Orthopteren, von Di 
Vitus Graber, 1875. 
