NOVITATES ZOOLOGICAE XXIII. 1916. 131 



1. Sychesia dryas Cram. (1775) (text-figs. 11-15, 41) 



In Cramer's figure the hindwing is blue-grey instead of yellow.* No such 

 species is known ; but as the figure is otherwise a fairly good representation of a 

 male of Sychesia, considering the time of publication, we assume with Hampson that 

 the colouring of the hindwing is due to some error. The specimen is said to have 

 come from the West Indies, which geographical term at that time included Surinam. 



We have three species from Surinam, obtained by Klages in the same locality 

 on clearings in the forest, at night only. These are subtilis Butl. (1878), omissus 

 Roths. (1910), and a third species which we treat, rightly or wrongly, as being 

 dryas Cram. (1775). The name fimbria Möschl. (1877) apparently applies to dryas. 

 The figure of fimbria is a misrepresentation, the head being much too small, the 

 colouring of the thorax and forewing much too red, and the marginal band of the 

 hindwing much too sharply defined and too narrow. 



S. dryas is known to me from Surinam, the Caura E.. in Venezuela, several 

 places on the Upper Amazons, East and South-Bast Peru, East Bolivia, and 

 South-East Brazil. In spite of this wide distribution there is no appreciable 

 variation in the organs of copulation, with the exception of our only Brazilian male. 

 The colour of the upperside of the forewing, head and thorax is mummy-brown 

 in the darkest (freshest?) specimens, and a light tint of raw umber in the palest 

 (faded ?) examples. The collar has usually a rufous tint, but there is no red 

 colouring noticeable at the base of the abdomen in any of our specimens. The 

 density of the pale irroration of the forewing and the size of the pale discocellnlar 

 spot are variable, as is also the width of the marginal border of the hindwing. In 

 the male this border is usually separated from the apex of cell by the very pale 

 yellow ground-colour or patches of it, but sometimes extends into the cell. In the 

 female the border reaches always into the apex of the cell and usually expands to 

 the base of the lower median vein, the angle between this vein and the cell 

 remaining yellow in many specimens ; on the underside the yellow area is still more 

 restricted, either entering the cell or being bounded in front by the cell and the 

 lower median vein ; in the latter case the patch is rounded distally, the fuscous 

 marginal band reaching to the anal angle and extending a little along the abdominal 

 margin, as it often also does on the upperside. 



The structure of the last three abdominal segments of the male is very 

 characteristic. The last external scaled segment is the eighth. It is black, as in 

 the other species, but quite different in the structure of its central dorsal portion. 

 This difference is easy io see in most examples. When inspected from the anal 

 side the apical margin of the eighth tergite will be found to be clothed with black 

 scaling on the upperside and yellow scaling on the underside. 



Compared with any of the other species, the central marginal area of this 

 tergite is thicker and projects anad, being separated at each side from the lateral 

 portion of the segment by a notch. If the scaling is removed the explanation of 

 this difference between dryas and the other species becomes at once evident. The 

 segment is centrally produced in dryas into a short broad process, which is very 

 slightly impressed centrally, convex above and at the margins, and hollow, mem- 

 braneous and longitudinally folded beneath. The corresponding portion of the 

 eighth tergite of the other species of the genus is but slightly produced and much 

 less thickened than in S. dryas (cf. text-fig. 25, viii. t.). This process, of which 



* Cramer's original drawings are in the British Museum ; in the drawing of dryas the hindwing 

 is less uniformly blue and the black border less sharply defined than in the published figure. 



