444 Considerations on the Genus Tetracanthagyna. 
wholly reddish, there are no pale bands on the sides of the 
thorax, a smoky blackish costal vitta extends from the 
base to the nodus (or slightly beyond), no dark bands on 
the wings, pterostigma whitish, neuration black, the area 
between the two sectors of the triangle not dilated and 
with only one row of cellules. About 36 antenodals and 
23 postnodals int he anterior wing. Length of posterior 
wing 60 mm. Length of abdomen (with appendages) 
63 mm. 
The anal characters are as follows :—There is a slight 
tooth at the extremity of the dorsal carina on the 9th 
segment, but the 10th is not sensibly produced at its 
extremity. There is a strong constriction at the j nction 
of the 6th and 7th ventral segments, reproduced in a 
smaller degree at the junction of the 7th and 8th (this 
seems to some extent to exist in the other spocies). 
Superior appendages slightly shorter than the 9th and 
10th segments, slender, foliaceous, (less twisted than in 
T. vittata), ending in a small sharp tooth. Inferior 
appendage one-half shorter, narrowing from base to apex, 
upcurved, the apex obtuse and slightly emarginate. 
A male from Deli (Sumatra) is described by Prof. 
Karsch in Entomol. Nachr. xvii. (1891), p. 345, and referred 
to 7. plagiata. The wing-expanse is given as 1385 mm., 
and the length of the abdomen as 90 mm. (thus the ex- 
panse is much less, and the abdomen considerably longer 
than in my & of 7. vittata); there is apparently no dark 
band on the wings. Nothing is said of the colour 
of the legs, or sides of the thorax, nor of :the condition. 
of the area between the sectors of the triangle. It is 
evidently very much larger than my male from Pulo Nias. 
A female example from Laha (Sumatra), in the Amster- 
dam Museum, is referred to 7. plagiata by Baron de Selys 
(Ann. Mus. Civ. Genov. (2), vii, p. 472). The length of 
the posterior wing is given as 74 mm.,and of the abdomen 
58 mm. Presumably it has a costal vitta and transverse 
band, but no details are to hand. 
DECEMBER 22, 1898. 
