Anato7ny of the Male Genital Tube in Cohoptera. 507 



band round the bulb (7)1) ; median orifice large, at distal end, with 

 ventral edge projecting beyond dorsal; median foramen small on 

 ventral face, about one-third from base. Lateral lobes attached to 

 median lobe on ventral aspect, at the ventral edge of the median 

 foramen. Internal sac large, with patches of short hairs ; details 

 not studied. 



Family TRICHOPTERYGIDAE. 



Form examined : Trichopteryx grandicollis Mann., Eng- 

 land, and some others. 



T. grandicollis (PI. LXXVII figs. 231 and 231r0. 



The aedeagus consists of a short tube with a pair of hooked struts 

 on the ventral side of the base, the median orifice large, with the 

 ventral edge produced into a blunt point. Internal sac large, 

 bearing small spines and a small chitin-plate {a) on the dorsal face 

 and some chitinisation on the ventral (J)) which we have not definitely 

 made out. The position of the opening of the duct on the sac was 

 not observed. 



We could find no trace of tegmen. A small plate with a central 

 strut exists below the aedeagus, but it appears to be a body sclerite 

 and not the tegmen. 



At present we are unable to associate this with any 

 other form. 



Euryptilium marginatum has the organ longer, with the 

 ventral margin of the median orifice projecting, pointed, 

 and turned down. 



Mr. H. Britten has submitted to us for examination 

 dissections of T. grandicollis, T. thorica, T. lovina, T. brevis, 

 EuryiJtilium marginatum, Ptiliolum sjjeyicei and an un- 

 identified species. These are each and all easily recog- 

 nised by the aedeagus. 



Family CORYLOPHIDAE. 



Forms examined : Sacium j^olitum (coll. Matthews), 

 hab. ? Coryloplms cassidioides Marsh., England. 

 Fig. 75 PL LIV. 



Sacium politum (PI. LIV figs. 75, 75rt). 



Median lobe a large flattened tube, the median orifice at the distal 

 end, the ventral edge extending beyond the dorsal and pointed; the 

 median foramen very small at the basal end. Tegmen forming a 



