Anatomy of the Male Genital Tube in Coleoptera, 587 
slender rod, the distal chitinisation being continued on to the 
internal sac which is small. G. mutator is similar to this, 
Obs.—Geotrupes is very remarkable and distinct. The 
tambour is very much closed, the basal portion of it is 
greatly reduced in size and the diameter there is con- 
siderably less than at the distal extremity, where the 
shape is very peculiar. The lateral lobes are of unusual 
form, and the distal chitinisation of the median lobe is 
strange, though it differs a good deal according to the 
species. Zyphocus is not so extraordinary as the other 
forms and may represent a distinct genus. 
Aclopus sp. 
Median lobe membranous. Lateral lobes long, thin and curved, 
basal half connected together by membrane. Basal-piece tambour- 
shape, much broader at base than at apex. The only specimen 
of this form at our disposal is so much damaged that we can say 
no more about it. 
Pachypus cornutus. 
Median lobe small, membranous; supported by a chitinous 
patch on each side, prolonged into long median struts. Lateral 
lobes fairly large, consolidated together for about one-third 
from their base on the dorsal side, and on the ventral side with 
membrane for about two-thirds from their base. Basal-piece large, 
tambour-shape, slightly flattened and asymmetrical. Internal sac 
large, covered with minute chitinous, pointed scales, 
Amphicoma vulpes (Pl. XLIV fig. 14). 
Median lobe small, visible, membranous except at base, with two 
median struts. Lateral lobes very small, free, their bases not 
touching on dorsal or ventral side, Basal-piece forming a long, 
thin, curved, chitinous tube, with basal opening at base on ventral 
side. Internal sac well developed and complex. It is difficult to 
distinguish the membranous median lobe from the sac as there is no 
line of demarcation. 
The very long chitin tube formed in this insect by 
the basal-piece is highly remarkable. In fig. 14 this part 
is by a lapsus marked m/ instead of bp; but the position 
of the median lobe is correctly indicated by the other mi 
near the tip. 
