Anatomy of the Male Genital Tube in Coleoptcra. 515 



Tegmen (fig. 85a) forming a ring-piece, the dorsal part being a hood- 

 shaped body, with a thin piece proceeding from each basal corner and 

 consolidating on ventral side of median lobe. Internal sac very 

 large, bearing armature near base (6) and towards apex (a). 



Family NITIDULIDAE. 



Forms examined : Psilotus atratus Reitt., Chiriqui- 

 Cychramus lutcus Fabr,, England. Ips (Glischrochihis of 

 various Ruihors) japonius Motsch., Japan. 



Figs. 87 and 88 PI. LVI. 



Psilotus atratus (PI. LVI fig. 87). 



Median lobe tubular, broad and flat, with single median strut. 

 Tegmen forming a large broad curved plate or hood, on dorsal 

 face, with a small dorsal median projection (a) from base, the basal 

 corners meeting and consolidating on ventral side of median lobe. 

 Internal sac large, the opening of ejaculatory duct at apex, where it 

 is supported by two chitin rods consolidated_ together at tip {b) round 

 the duct opening. 



Ips japoniiis (PI. LVI fig. 88) 



is of the same type as P. atratus; and so is Cychramus, the "hood"' 



being much larger than the median lobe. 



The family Monotomidae comes near to these forms, 

 as also does Helotidae. On the other hand, Rhizophagus 

 does not belong to Nitidulidae. Whether it can be 

 satisfactorily placed in Cucujidae (where we have treated 

 of it, cf. fig. 101), can only be determined by a much 

 more extensive survey of the Cucujidae than we have 

 made. 



Family BYTURIDAE. 



Form examined : Byturus tomentoms Fabr., England. 

 Fig. 86 PI. LVI. 



Byturus tomentosus (PI. LVI fig. 86). 



Median lobe long, slender, and pointed; median orifice at tip on 

 dorsal face ; median foramen at base. Tegmen forming a close- 

 fitting sheath, the distal half chitinous, the basal half membranous, 

 with a strip of chitin supporting each side (a) ; and a Y-piece 

 with a long stalk (h) supporting the ventral aspect. Internal sac 

 undifferentiated. 



This type is similar to Trogositidae. 



