Anatomy of the Male Genital Tube in Coleoptera. 507 
band round the bulb (m) ; median orifice large, at distal end, with 
ventral edge projecting beyond dorsal; median foramen small on 
ventral face, about one-third from base, Lateral lobes attached to 
median lobe on ventral aspect, at the ventral edge of the median 
foramen. Internal sac large, with patches of short hairs ; details 
not studied. 
Family TRICHOPTERYGIDAE. 
Form examined: TZ'richopteryx grandicollis Mann., Eng- 
land, and some others. 
T. grandicollis (Pl. LX XVII figs. 231 and 231¢). 
The aedeagus consists of a short tube with a pair of hooked struts 
on the ventral side of the base, the median orifice large, with the 
ventral edge produced into a blunt point. Internal sac large, 
bearing small spines and a small chitin-plate (a) on the dorsal face 
and some chitinisation on the ventral (b) which we have not definitely 
made out. The position of the opening of the duct on the sac was 
not observed. 
We could find no trace of tegmen. A small plate with a central 
strut exists below the aedeagus, but it appears to be a body selerite 
and not the tegmen. 
At present we are unable to associate this with any 
other form. 
Luryptilium marginatum has the organ longer, with the 
ventral margin of the median orifice projecting, pointed, 
and turned down. 
Mr. H. Britten has submitted to us for examination 
dissections of 7. grandicollis, T. thorica, T’. bovina, T. brevis, 
EHuryptiium marginatum, Ptiliolum spencei and an un- 
identified species. These are each and all easily recog- 
nised by the aedeagus. 
Family CORYLOPHIDAE. 
Forms examined: Saciwm politwm (coll. Matthews), 
hab.? Corylophus cassidioides Marsh., England. 
Fig. 75 Pl. LIV. 
Sacium politum (Pl. LIV figs. 75, 75a). 
Median lobe a large flattened tube, the median orifice at the distal 
end, the ventral edge extending beyond the dorsal and pointed; the 
median foramen very small at the basal end. Tegmen forming a 
