Classification of the British Geometridae 



based on the structure of the male and 



female Genitalia. 



GEOMETRIDAE. 



GNATHOI. 



Geometrinae. 



Valva elongate generally simple. Uncus bifurcate or if 

 single with protruding socii. In situ the uncus is folded 

 over the gnathos. Gnathos rarely strong. .ZEdceagus stout 

 or more generally pistillate. Eighth segment developed 

 often scobinate. Coremata on ninth segment. 



Hipparchis papilionaria, L. 63 



Valvula peaked, narrow; costal fold short; sacculus ex- 

 tended. Transtilla large rounded plates. Uncus bifid, 

 widely divided. Gnathos point long, weakly scobinate. 

 ZEdceagus pointed. Saccus lobed at centre, with central 

 inward projection. Margin of eighth sternite bilobed. 



Ostium small. Ductus bursae weak. Signum small, 

 double pointed. 



Pseudoterpna pruinata, Hufn. 62 



Valvula narrow; harpe raised, long, heavily spined. Uncus 

 bifurcate", pads hairy. Gnathos squared, scobinate. 

 ^Edceagus narrowed towards tip, orifice with long serrated 

 arm. Saccus pointed. Coremata short, on ninth segment. 



Ostium weak. Ductus bursae thickened. Bursa 

 elongate. 



It has been questioned if coronillaria, Hb. is not a 



