584 MR. A. M. ALTSON ON THE 
oi: a uni('oi-m thickness of cliitin except towards their base, where the inner 
face becomes thin and flexible. Each lateral lobe contains a group of muscles 
and nerve-fibres extending to their apices (PI. 31. fig. 2). At their base the 
lateral lobes become joined together ventrally and dorsally ; at the latter 
point they join around the point of articulation (pa). Externally the 
median lobe and the lateral lobes bear sensory pits at their apices. 
Enclosing the base of the lateral lobes is a thin piece of chitin, the basal 
piece (bp), which appears to clip the dorsal edges of the lateral lobes below 
the point of articuhition. Arising from the surface of the basal piece 
towards its posterior margin is the flexible enveloping integument of the 
abdomen. 
In sections of a male the spermatozoa were found in bundles, held 
together at their heads. In balsam mounts of the dissected genitalia these 
bundles could also be seen within the testicular follicles when the organs had 
been stained in hsemalum and indigo-carmine. 
Between the dorsal pygidial plate [dp) and the cerleagus is a chitinous tube 
[ev) which completely envelops the anus (an) and anterior portion of the 
rectum {r) (PI. 31. figs. 2 & 3). Each side of the chitinous tube (ev) 
invaginates to form a pair of stout rods {vr, fig. 3). These rods surround 
the oedeagus and abut at their base, which is towards the ventral surface 
of the abdomen. From the base of the rods there are three primary sets of 
muscles (m). Two of these sets follow the course of the rods and terminate 
around the chitinous tube ; the third set runs between the rods and is attached 
to the enveloping integument below the base of the oedeagus ; some of these 
muscles appear to be attached to the oedeagus ventrally. 
From this it would appear that the latter muscles are primarily responsible 
for giving the oedeagus its necessary downward tilt preparatory to coition. 
Folloi\ing the alimentary tract back from the anus {an, PL 31. fig. 5) is 
the rectum (r), which is quite short and lies dorsal to the oedeagus and 
ejaculatory duct. Beyond the rectum is the colon (cl) lying dorsal to the 
accessory glands, part of the ejaculatory duct, and the seminal vesicles. 
Beyond the colon is the ileum, which disappears below the testicular 
follicles and lies towards the ventral surface of the abdomen. There are six 
malpighian tubes (mp) arising from the ileum, which at this point is lined 
with chitinized setse. Beyond the ileum is the mesenteron («i«), which lies 
in the meta- and mesosternum, where it inclines towards the dorsal surface. 
Arising from between the metathoracic acetabula (mta) is a " U "-shaped, 
strongly chitinized apodeme (ap); the base of the " U " arises from the meta- 
sternum (</), whilst the apices of the arms are held in position by muscles 
attached to the metanotum. From inside the " U "-piece and from its base 
arise two thin chitinous rods (apr). These rods traverse the floor of the 
metasternum and terminate above the metathoracic coxse {mc), to which 
they are attached by radiating muscle-fibres. 
