Anatomy of the Male Genital Tube in Coleoptera. 593 
greater part of their length. Lateral lobes large, symmetrical ; 
consolidated on dorsal and ventral faces at base. Basal-piece large, 
tambour-shape with a ventral plate (vp) connected to the basal 
ventral edges of the lateral lobes by membrane, not consolidated to 
them. Internal sac large with four long thin diverticula at apex, 
covered with hairs, no armature. 
We have examined several species of Hexodon and find they fall 
into two groups, one with symmetrical lateral lobes and four 
diverticula of sac; the other with asymmetrical lateral lobes and 
five diverticula. 
Ancognatha vulgaris, 
Median lobe moderate in size, membranous with chitinous 
support near base. (In some Scarabaeidae the chitinous support 
of the median lobe appears to appertain rather to the second 
connecting membrane, but we have described it as belonging 
to the median lobe as only a detailed study in many forms could 
elucidate ‘this.) Basal-piece of the usual tambour-shape, its con- 
cave aspect membranous, its dorsal more feebly chitinised than in 
the normal Dynastinae ; the sides of this sclerite prolonged distally 
so as to form a point on each side to which are articulated the very 
peculiar lateral lobes. These, viewed laterally form a sort of V, 
between the branches of which the distal point of the basal piece (as 
described above) penetrates. The lateral lobes are not in this species 
amalgamated by chitin but exist as two sclerites connected by 
membrane. Viewed on the convex aspect of the aedeagus in repose, 
the two sclerites become contiguous, their inner margins being 
nearly straight ; each is a little truncate at the tip, and on the outer 
side has a small, sharp hook, On the concave aspect, the sclerite is 
larger than on the other aspect, but the inner margins are parallel 
here also. These lateral lobes are capable of divarication, and it 
appears that this permits the extrusion of the median lobe, 
Internal sac large and complex, the apical half greatly enlarged, 
with two small diverticula near opening of ejaculatory duct at apex, 
and a long thin diverticulum opening near middle; no chitinous 
armature, but surface covered with short fine hair, 
Cyclocephala stictica. 
In this the lateral lobes are greatly abbreviated and form a ring 
at the end of the basal-piece, This ring, being placed at a right 
angle to the axis of the aedeagus, is articulated on each side to the 
distal point of the basal-piece ; except at this spot the connection 
of the lateral lobes with the basal-piece is entirely membranous, 
As the ventral plate of the basal piece is to some extent elastic, 
