Anatomy of the Male Genital Tube in Coleoptera. 501 
points basally. The aedeagus in Lathrobiwm is extremely irregular 
and asymmetrical in structure. 
Stenus speculator (Pl. III figs. 70, 70a). 
Median and lateral lobes on same plan as Paederus riparius. 
Internal sac large, with two chitin strips (a). These chitin strips 
are continuations of the chitin of the ventral surface of the median 
lobe. 
Osorius sp. (Pl. LIV fig. 72) from Trinidad, apparently has the 
lateral arms entirely missing, or reduced to a narrow, small band 
slightly distal of the median foramen on the ventral side (Il), The 
median lobe is bulbous with the dorsal side semi-membranous and 
the ventral distal edge pointed. The internal sac is large with two 
diverticula near base, one bearing short hairs on the tip, and a large 
curved diverticulum at end, ventral of the opening of ejaculatory 
duct. 
Nodynus lewcofasciatus, 
Median lobe bulbous at base, chitinous on ventral side and drawn 
out distally to a point, the dorsal side being membranous ; median 
orifice at distal end on dorsal side; the median foramen small, on 
ventral side and about the middle. Lateral lobes fairly broad, 
pressed against sides of the median lobe and projecting slightly 
beyond tip, attached to median lobe on ventral side of edge of 
median foramen. Internal sac without chitinous armature. 
This is very Silphid-like, but the absence of the basal-piece 
separates it from that group. 
Olophrum piceum is very like Nodynus, the lateral lobes being 
flattened and curved. Internal sac long, flattened and coiled up in 
the median lobe ; its surface covered with hair-like scales. 
Leptochirus, sp. 
Median lobe tubular, curved ventrally near the base ; semi- 
chitinous on dorso-basal part. Median orifice on dorsal side of tip ; 
median foramen small, near base on ventral isde. Lateral lobes 
small, about one-fifth the length of the median lobe. Internal sac 
large, but not examined. 
Zirophorus bicornis (Pl. LIV fig. 73). 
Has a thin, slightly flattened median lobe, strongly chitinised 
and curved at the base, and semichitinous along the dorsal basal 
part (m). The lateral lobes are articulated to the curved base and 
consist of narrow lobes free along their whole length. Median 
orifice at distal end, median foramen at base. Internal sac short 
and without armature, 
