LIBELLULIN A. 201 
abdomen ; arculus of the front wing between first and 
second antenodals soe ee . ERyYrHRopirPiax™®. 
NN. Males with genital hamule not branched, females with 
vulvar lamina not projecting; sectors of triangle of hind 
wing arising from same point. 
O. Hind wing with nodus nearer to stigma than to base, 
area between the rounded anal “ angle” and proximal 
subbasal sector with the cells arranged in rows sub- 
parallel to that sector and to the margin, that sector 
unbranched. 
P. Middle of the field between subnodal sector and 
supplementary sector next below with two (except 
in most [?] D. cannacrioides) rows of cells, nodal 
sector usually waved in the middle, front wing with 
triangles cross-veined and at least three post- 
triangular rows from the discoidal triangle out- 
ward; tooth of tarsal claws always shorter than 
tip of claws itself. 
Q. Abdomen not abruptly widened on segments 7-9 ; 
males with the antero-inferior row of teeth on 
the second and third femora inclined, if at all, 
toward the same direction. . . . DytHemis. 
QQ. Abdomen abruptly widened on segments 7-9, 
males with the antero-inferior row of teeth on 
second femora inclined toward the knee, on 
third femora toward the trochanter. . . - ([Scapanea f. | 
PP. Middle of the field between subnodal sector and 
supplementary sector next below with only one row 
of cells, nodal sector not waved in the middle, 
front wing with not more than two post-triangular 
rows in at least part of the area proximal to the 
nodus, teeth on femora of males as above for 
Scapanea. 
R. Tooth of tarsal claws shorter than tip of claw 
itself, front wing with discoidal triangle cross- 
veined or free. . . . . . . . . . . . BrecuMornoga. 
* Differs from Trithemis of the Old World in having the vulvar lamina of the female projecting, the outer 
branch of the genital hamule of the male longer than the inner branch, and in some other characters to which 
different species on both sides offer some exceptions, such as the shorter distance in which the eyes are in 
contact, the subrectangular form of the middle portion of the hind prothoracie lobe, &c. 
+ Known only by one species, S. frontalis, Burm., from the West Indies, but possibly occurring within the 
present region. 
