Seitz:

S. Cassandra L. (15 f) is very much like nigripalpia, of a more brown ground-colour with darker veins and a faded discoidal spot, also between the median veins there is darker colouring. The base of the palpi and borders of the collar are red. Widely distributed from Venezuela to xArgentina, also in Trinidad.
S. nigripalpia Hmps. (= cassandra Druce) (15 g). Clumsy, unicolorously black species with densely scaled wings. Vertex, shoulders and collar with metallic blue spots. Sides of thorax, middle and posterior hips, the first abdominal ring above and at the sides, and the base of the shoulder-covers exhibit scarlet spots.
The abdomen shows lateral metallic bluish-green spots, and the apex of the abdomen is scarlet. The quite black palpi separate the species from the similar, though more brownish cassandra. Common in the whole of Mexico (from May to August). In Costa Rica there flies a form more similar to cassandra: — costaricae Strand (= subsp. 1 Hmps.) in which the wings turn brownish between the veins, the metallic blue spots being absent on the head and thorax.