on the Genus Tetracanthagyna. 441] 
symmetrically irregular in the ¢ individual before me, although 
regular in the posterior wings) ; nodal sector much bent just before 
the pterostigma (somewhat as in {the genus Hemianax), with severa! 
double cellules below the bend ; 4—5 rows of cellules between the 
subnodal sector and its branch; 5 cellules between the subnodal 
and the interposed sector at the widest part ; a single row of cellules 
between the sectors of the triangle. (In the posterior wings the 
area between the sectors of the triangle is dilated for some distance, 
with two rows of cellules, followed by one row.) 
¢. Anal triangle 3-celled ; the inner upper cellule formed by an 
oblique nervule (in one wing there is a small supplementary cellule 
on the inner margin). On the abdomen the oreillettes are sub- 
quadrate, black, finely limate on the edge. The 8th dorsal segment 
is produced into a small acute tooth in the middle of its posterior 
margin, on either side of which are smaller teeth; the 9th has a 
stronger and blunter tooth-like production, and in the 10th there is 
a terminal hump, in all cases extensions of the dorsal carina, which 
on the 10th is much elevated, and has a deep broad sulcus on either 
side. Appendages black ; the superior about as long as the 9th and 
10th segments united (8 mm.), inserted well below the elevated 
hump of the segment, foliaceous, but slender, nearly straight, but 
slightly curved upwards from the middle; viewed above the inner 
edge is gradually dilated from base and apex to the middle, the tip 
ending in a sharp out-turned tooth or spine ; the apical portion for 
some distance is occupied internally by a deep groove bounded by 
the longitudinal carina and occasioning a torsion which causes an 
appearance as of an obtuse subapical dilatation if viewed laterally . 
the apical half internally has a strong fringe of hairs. Inferior 
appendage one-third shorter, upcurved if viewed laterally, slender, 
gradually narrowing from the base, it is suleated above, and the apex 
is obtuse and slightly emarginate. 
2. The 8th and 9th dorsal segments strongly produced into a 
triangular tooth in the middle of the posterior margin, 10th scarcely 
produced, but there are a few apical denticules. Appendages short, 
black, straight, styliform and cylindrical, scarcely extending beyond 
the abdominal extremity. Tenth ventral segment having (in the 
individual before me) three large and one small acute teeth. Valves 
of the 9th segment not extending to apex of 10th, with black filiform 
appendages. 
Length of abdomen ¢ 80 mm. (with appendages), 9 70 mm. 
Length of posterior wing ¢ 75 mm., 9? 80mm. Greatest breadth 
of posterior wing ¢ 23 mm., 2 22mm. Expanse of anterior wings 
¢ 159 mm., 9 169 mm. 
