Anatomy of the Male Genital Tube in Coleoptera, 641 
tion is varied, Although this point is not of great importance for 
our purposes, the scale is in most cases indicated by a line placed 
near the figure. When no number accompanies the line then the 
length of the line is 1 mm. and the magnification of the figure is 
indicated by that of the line. When a number accompanies the 
line, the number indicates the length of the line in millimetres or a 
fraction of one. 
The connecting membranes between certain parts are only par- 
tially shown in the figures. To have invariably introduced them 
would have involved the use of shading ; and much artistic ability 
would even then be required to distinguish the scleritic from the 
membranous parts. The student will recollect that these membranes 
always exist connecting the median lobe to the tegmen, and the 
tegmen to the body wall. Sometimes a part of one of the membranes 
is shown, and it is then indicated as such by the torn edge. 
The position shown is very frequently not a true profile, but a 
partial one, thus allowing more of the parts to be seen and inferred. 
The drawings have all been made from specimens in a wet, or 
relaxed, state ; and the student must not expect to find exactly the 
same appearances in dried and collapsed preparations. 
The figures are as a rule uniform as regards their longitudinal 
position, the distal end being to the right so that a side-view shows 
the left side. In a few cases, in order to show certain structures, 
the right (not the left) side is figured ; and in that case in order to 
make comparison more easy the figure is orientated so as to make 
the right side look as if it were the left one, and it is stated to be 
“reversed.” 
Broken lines indicate parts that are lying below the structures 
represented by unbroken lines, They are introduced to show the 
continuity of portions that are not actually seen in such a dissection 
as that figured. Where these concealed parts are the sac and the 
duct the broken lines are reduced to dots. 
We use both single and double letters to indicate special parts, 
The double letters are used uniformly throughout the figures, and 
are explained below this, and more fully on pp. 481-483. The 
meaning of a single letter will be found by reference to that 
descriptive portion of the memoir to which the figure pertains, 
EXPLANATION OF DouBLE LETTERS. 
aed = aedeagus. 
an = anus. 
bp = basal-piece. 
cm 1 = first connecting membrane. 
