Anatomy of the Male Genital Tube in Coleoptera. 575 
This is a very interesting form, in connection with the 
question of the function of the flagellum generally. Does 
the portion of the sac that can be evaginated (to the 
extent of at least 10 mm.) act in a similar way to the 
highly developed flagellum of Lucanus ? 
Systenus caraboides (Pl. XLIII figs. 7 and 7). 
The median lobe is formed of a strong bilobed plate on the 
ventral side, with a ridge across each lobe (a, fig. 7a), the one on the 
right being larger than the one on the left; the dorsal side is 
membranous, except at the base round the small median foramen, 
where there is a ridge for the point of articulation (pa) and the 
attachment of the median struts. The lateral lobes are broad, 
short and truncate and embrace the basal sides of the median lobe, 
but do not meet either on the dorsal or ventral faces. The basal- 
piece is large, shield-shaped, with the edges turned up ; the dorsal 
side being membranous. The internal sac is large and complex and 
is permanently evaginated and bears a short flagellum (fg) through 
which the ejaculatory duct passes to the orifice at the tip, When at 
rest the sac collapses upon itself and lies on the dorsal side of the 
median lobe, but under blood pressure swells out (fig. 7a). 
Lucanus cervus (Pl. XLIII fig. 8) and Chiasognathus 
grante. 
Are on the same plan as S. caraboides, but the flagellum is 
very greatly elongated. 
Figulus marginalis. 
Median lobe small, tubular and curved, with a pair of median 
struts consolidated along their basal half, the internal’sac is fairly 
large and appears to be permanently everted and has no flagellum. 
Lateral lobes small. Basal-piece about twice as long as the lateral 
lobes, forming a slightly flattened tube ; from the distal edge of the 
ventral side there is a small curved tongue which covers and hides 
the median lobe. 
F, striatus. 
Is of the same type but hasa long flagellum. The question of 
these two species remaining in the same genus is doubtful. This 
type approaches Sinodendron. 
Neolamprima adolphinae (Pl. XLIV figs. 10 and 10a). 
Has along, strong, cylindrical basal-piece, with small lateral lobes. 
The median lobe is small, thin and cylindrical, with two short 
QQ 2 
