Anatomy of the Male Genital Tube in Coleoptera. 581 



The tegmen of this comes near to the Trogositidae, but 

 the median lobe is quite unique so far as we have 

 observed. 



Family GEORYSSIDAE. 



Form examined : Georyssus pygmaeus Fabr., England. 

 Fig. 124 PI. LXII. 



G. pygmaeus (PI. LXII fig. 124). 



Trilobe form, flattened horizontally. Median lobe flattened, 

 pointed at tip. Lateral lobes flattened, rounded at apex, concave 

 along the inner edge so that the median lobe can fit into the con- 

 cavity, and so become nearly hidden. Basal-piece large, chitinous 

 on ventral face, membranous on dorsal. Sac not examined. 



This is a trilobe form, and reminds one of some of the 

 Gyrinidae. It cannot be placed with Cyathoccrus. 



Family HETEROCERIDAE. 



Form examined : Hrtcroccrus flexuosus Steph., England. 

 Figs. 12.5 and 125a PI. LXIII. 



H. flexuosus (figs. 125, 125rt). 



Median lobe large, chitinous on ventral and lateral faces, mem- 

 branous on dorsal, produced into short bilobe strut {m,s) at base, the 

 apical point slightly turned aside. The internal sac appears to 

 be permanently everted and, when at rest, twisted up on the dorsal 

 face of the median lobe. Tegmen forming a large cap on dorsal 

 aspect of median lobe, produced into a broad strut at base, slightly 

 emarginate at apex, and the lateral edges turned down and envelop- 

 ing the side of the median lobe, but only connected by membrane 

 (m) on the ventral aspect. 



Family PARNIDAE (= Dryopidae of some). 



Forms examined : Felonomtcs palpalis Si)., Central 

 America. Parnus luridus and other species, England. 

 Figs. 126 and 127 PI. LXIII. 



P. palpalis (PI. LXIII fig. 126). 



Median lobe long, slender and slightly curved, the median 

 orifice on ventral aspect near tip, base articulated to base of lateral 

 lobe on dorsal aspect {pa). Lateral lobes large, pointed at tipp. 



