200 
in the body. Towards the end of femur the one trunk 
is increasing in thickness and is turning to the side 
at the distal end of patella and goes to the spiracle 
lying in the basis of tibia (Tab. IV, fig. 2, g). Itis con- 
siderably narrowed in the last, short piece; a trunk (h) 
is rising where the narrowing is commencing, being 
much narrower than the main trunk and running nearly 
through the whole length of tibia about to the metatarsus 
where it seems to be dissolved into fine branches. 
Before the entering of the main trunk into the spiracles 
is taken place fine, recurrent branches (i) issue from 
it. I have found them recurrent on preparations cleaned 
in caustic potash, and in August this year I. have 
examined a fresh specimen of an Acantholophus (with 
the tracheal trunks filled with air) and have also found 
them to be recurrent. The proximal spiracle appears 
chiefly to supply fresh air to the main trunk in patella 
and the distal portion of femur, besides partly to tibia, 
and only appears as an aperture, establishing 
a connection by a short lateral tracheal branch 
withthe widest of the2normal trunks of theleg 
which issues from the central trachealsystem, 
while the distal spiracle posseses a special 
tracheal system which but secondary communi- 
cates with the other of themain trunks and which 
doubtless, to no small extent, provides with air the distal 
portion of tibia, besides metatarsus and tarsus. Making 
use of dissection of tibize cleaned in caustic potash I 
have studied the structure as well as possible, but I 
abstained from giving any figure, as several of the tracheæ 
were collapsed and I was afraid of not being sufficiently 
exact in the representation of details. The direction 
and ramification of the trachex I have later (in August) 
studied on fresh specimens (of Phal. cornutum), put 
into glycerine which does most excellently preserve the 
