Anatomy of the Male Genital Tube in Coleoptera. 517 
lateral lobes joined together on their ventral aspects and forming a 
large plate ; the median distal portion of the plate projecting between 
the distal ends of the lateral lobes as a free process, truncate at 
tip (b). No differentiated internal sac. 
In this species there is a distinct abdominal plate between the 
anus and aedeagus (lv), which we think must be the last ventral 
sclerite of the body. 
Tarphiomimus indentatus is of a similar type (Pl. LVIT fig. 98). 
Aulonium bidentatum (Pl. LVIT figs. 91, 91a). 
Median lobe large, somewhat flattened ; median orifice near tip 
on ventral face. Tegmen formed of a large basal-piece, chitinous on 
ventral and membranous on dorsal aspect, and a large piece, formed 
of the lateral lobes consolidated together to near their tips, on the 
ventral face. 
Deretaphrus ignavus (Pl. LVII figs. 94, 94a). 
Median lobe long, slender and tubular, with median orifice at tip 
on dorsal side, median foramen at base, which is slightly swollen. 
Tegmen consisting of two short, broad lateral lobes, rounded at tip 
and bearing a strong curved spine at base, between which the median 
lobe passes. Basal-piece short, projecting as two short struts (a) at 
base. Internal sac undifferentiated. 
Some other species (which cannot be determined but are not 
D. piceus, the type of the genus) are of the same construction with 
slight difference in details. 
Cerylon histerordes (Pl. LVII fig. 95). 
The aedeagus consists of a long, tubular median lobe, swollen at 
its apex, across which is the median orifice; and a small ring- 
shaped tegmen articulated at the base of the medianlobe. Internal 
sac complex, 
Obs.—There is great diversity among the few forms 
of Colydiidae we have examined. 
We might perhaps associate Hnarsus and Auloniwm, 
though there is much difference between them. Hnarsus 
is one of the connecting links of the trilobe aedeagus with 
the sheath-forms (Trogositidae, etc.) that we have at 
present placed in Cucujoidea. We have therefore in our 
table also given this genus a place in Byrrhoidea. 
Aulonium is more definitely Trogositoid. 
Deretaphrus is not thoroughly elucidated. There may 
