Anatomy of the Male Genital Tube in Ooleoptcra. 575 



This is a very interesting form, in connection with the 

 question of the function of the flagellura 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 carahoides (PI. 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. 7o), 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. la). 



Lucanus cervus (PI. XLIII fig. 8) and Chiasognathus 

 granti. 



Are on the same plan as S. carabuides, but the flagellum is 

 very greatly elongated. 



Figvlus viarginalis. 



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 flagellura. 

 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. striatum. 



Is of the same type but ha s a long flagellum. The question of 

 these two species remaining in the same genus is doubtful. This 

 type approaches Slnodendron. 



Neolamprima adolphinae (PI. XLIV figs. 10 and 10a). 



Has a long, strong, cylindrical basal-piece, with small lateral lobes. 

 The median lobe is small, thin and cylindrical, with two short 



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