NOVITATES ZOOLOGICAE XXIII. 1916. 141 



According to the male genitalia there are two geographical forms : 



a. S. subtilis megalobus subsp. nov. (text-figs. 25-29, 44) 



Harpe with a very large apical lobe (text-fig. 29, L 1 ) ; process P 1 of the ninth 

 segment dorsally convex apically. 



A series in the Tring Museum from Aroewarwa Creek, Maroewym Valley, 



Fig ss 



Text- fig. 28. — Sychesia subtilis megalobus, ventral view of clasper and penis-sheath. 



Surinam, February (S. M. Klages), type ; La Union and Guaypa, Caura R., 

 Orinoco, October, November, December, April, May (S. M. Klages) ; Trinidad 

 (F. Birch). 



b. S. subtilis subtilis Butl. (1878) (text-fig. 30) 



Apical lobe of harpe small (text-fig. 30, L 1 ). Process P 1 of the ninth 

 segment apically compressed ; process P 2 shorter and slenderer than in megalobus ; 

 apex of the tenth tergite dorsally more convex. 



The type of subtilis came from the Rio Sapo, Amazons, caught on December 13, 

 1874 ; the other specimens mentioned by Butler as far as they are preserved in the 

 British Museum are S. dryas dryas, for instance the second Rio Sapo example 

 caught on December 14. As the specimen labelled by Butler " type " is the present 

 insect, the name should be retained for this species, although Hampson has sunk 

 the name as a synonym of S. dryas. I cannot find the Rio Sapo ; is Sapo a mis- 

 spelling of Napo ? In the Tring Museum another male, obtained on board the 



