1928] 
The Male Genital Tube of the Amphizoidce 
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cylindrical tube with a large median orifice (MO) extending the 
greater part of the length of the ventral side, internal sack (IS) 
simple and undifferentiated. The lateral lobes (LL) are large, 
produced, and coming together to form an articulation with the 
median lobe on the dorsal side. When retracted into the ab- 
domen the sedoeagus lies on its left side. The basal plate (BP) is 
small, attached to the lateral lobes by a short membrane, and 
rides over the lateral lobes. The structure of the sedoeagi of the 
three species varies only in details of size and shape of the 
median lobe, the lateral lobes, and the basal plate. 
The sedoeagus of the Caraboidea Series is of two types, the 
less specialized being characterized by an undifferentiated in- 
ternal sac. The Pelobiidse, Halipidse, Dytiscidse, and Amphi- 
zoidse possess such a simple sac. From a comparison of the 
figures by Sharp and Muir the Amphizoid sedoeagus seems to be 
more closely related to the Pelobiidse in the structure of the 
basal plate, and the size and shape of the lateral and median 
lobes. 
The general shape of the Amphizoid sedoeagus resembles 
that of Dactylosternum subdepressum Cast, which belongs to the 
Byrrhoid series of Sharp and Muir. In Dactylosternum the 
lateral lobes meet on the ventral surface, while in Amphizoa 
they meet and articulate with the median lobe on the dorsal 
surface. The basal piece in Dactylosternum is chitinized entirely, 
in Amphizoa the basal piece is not chitinized on the dorsal surface. 
This resemblance in shape then is only a superficial one. 
