Anatomy of the Mcde Genital Tube in Coleojjtcra. 557 



Family TRICTENOTOMIDAE. 



Form examined : Trictenotoma thoiiisoni Deyr., hab. ? 

 Figs. 194 and 194r^ PI LXXII. 



Trictenotoma thomsoni (PI. LXXII figs. 194, 194a). 



Median lobe long, thin and curved upward at the base ; the apex 

 chitinous, continued as a chitin strip along the ventral face, at the base 

 this chitinous strip is a curved bar {b) which connects with the tegmen. 

 Tegmen consisting of a well-defined basal-piece (bp) with a large 

 sclerite («) on the ventral aspect of the median lobe ; near the base 

 of the sclerite (a) arise two long thin lobes, spatulate at tips and 

 hairy. The bars (/>) from the median lobe are connected with the 

 lateral basal edges of the large sclerite and form a spring which 

 brings the median lobe back into position when the muscles are 

 relaxed. Internal sac undifi"erentiated. The large sclerite may repre- 

 sent the lateral lobes of other forms, as it is closely connected with 

 the basal-piece ; in that case the remarkably long lobes (II), are 

 secondary differentiations, or appendages of the conjoined lateral 

 lobes. 



This is a beautifully constructed organ. It is a little 

 like Pytho, but the orientation of the tegmen is reversed 

 and in that respect approaches Pyrochroidae. 



Family BRUCHIDAE (Lariidae of some). 



Forms examined : Bncchus rufimaiius Boh., England. 

 Garyohorus nuclcoruiii Fabr., Brazil. G. sp. ? (not named in 

 Brit. Mus.), S. America. 



Figs. 195, 196 and 197 PI. LXXII. 



Bruchus rufimanus (PI. LXXII figs. 195, 195a). 



Median lobe tubular, with the dorso-basal margin produced into 

 a parallel-sided strut (s), the median orifice being at the apex. 

 Tegmen forming a ring-piece with a pair of lateral lobes on the dorsal 

 aspect and a wide strut on the ventral aspect. Internal sac large 

 with armature at the base closing the orifice, consisting of a curved 

 spine (a) on the ventral face and a chitinous plate (6) on the dorsal. 



Garyohorus sp. ? (PL LXXII fig. 196). 



Median lobe a flattened tube, with the ventral and dorsal edges of 

 the median orifice pointed, the ventral one produced beyond the 

 dorsal one, thus giving the orifice a slit-like shape on the dorsal 

 face; the dorso-basal edge is produced into a single dorsal strut, 



TRANS. ENT. SOC. LOND. 1912. — PART III. (DEC.) PP 



