Anatomy of the Male Genital Tube in Coleo2')tera. 493 



and Cicindelidae. In the latter two families the median 

 lobe is a more or less perfect tube with the median orifice 

 at or near the distal end, and the median foramen at the 

 basal end ; in the three other families it forms a chitinous 

 organ, grooved along the ventral surface (or the lateral 

 margin turned down), with a membranous tongue cover- 

 ing the basal part of the groove. There being no differ- 

 entiated sac it is impossible to say how much of the 

 ejaculatory duct is evaginated during coition.* 



Unfortunately the only Amphizoidae we could procure 

 were females. 



Family GYEINIDAE. 



Forms examined : Enliydrus sp. n., aff. E. atrati, Lita, 

 4000 ft. Gyrinvs nataior and urinator, EnglaQd, Orecto- 

 chilus disjMT Walker, Ceylon, 



Figs. 42, 43 and 43a PI. XLIX.- 



Gyrinus natator (PI. XLIX Hg. 42). 



Median lobe pliglitly flattened and curved ; tip truncate ; dorsal 

 and lateral parts chitinous ; niedian orifice forming a narrow slit on 

 tlie membranous ventral side near tip ; median foramen at base. 

 Lateral lobes flattened horizontal!}', narrow at base and gradually 

 widening to truncate apex, which bears long hairs ; consolidated 

 along ventral basal half and near base on dorsal side. Median lobe 

 articulated to base of lateral lobes on dorsal side. Basal-piece large, 

 forming a large chitinous plate on ventral and lateral sides ; mem- 

 branous on dorsal side; membrane connecting it to lateral lobes 

 large and allowing great movements of parts. No differentiated 

 internal sac. 



Enhydrus, sp. 



This is the same type as G. natator, the median lobe being 

 pointed and the lateral lobes pointed on the inner side of a widened 

 tip. Basal-piece large, but connecting membrane not so large as in 

 G. natator, and not allowing so much movement between basal-piece 

 and lateral lobes. No differentiated internal sac. 



Oretochilus dispar (PI. XLIX figs. 43 and 43a). 



Median lobe tubular, drawn to a point on the ventral side of the 

 apex ; median orifice situated on dorsal side of apex ; median fora- 



* F. Netolitzky (Deut. Ent. Zeitschr., 1911, p. 271) has discussed 

 the Adephaga from the point of view of the lateral lobes. 



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



