Vo" 98] ENTOMOLOGICAL News. 431 
; Group IV has 8-12 cross-veins in front wing and 
in hind wing. 
vf i¢ three genera with 4-sided triangles in the front wing, 
Cordul: is remarkable by the great divergence of M 5 
laps and the convergence of M, and Cu, in the front 
, and the reduction of wing area. It suggests Syncordulia. 
ya is its exact opposite in all these characters and sug- 
Idionyx. Pentathemis has as little in common with the 
& er two as they have with each other, the 4-sided triangle of 
_ the front wing resulting from an entirely different switching of 
veins. It is related to Aeschnosoma and perhaps should be 
em er. 
PLATYCORDULIA new genus.* 
-_ Related to Neurocordulia, Aeschnosoma and Libellulo- 
soma, Distinguished at once from all by the apically broad- 
ny and rounded anal loop which is widely  sep- 
a from the wing margin by 2 rows of cells (one row 
te inall the others). Of the four genera it has the densest reticula- 
: tion. The two genera Aeschnosoma and Libellulosoma are close- 
Wy rlated to each other and are distinguished from the other two, 
_ among other characters, by the strongly waved Ms and M , 
_ in both front and hind wings and the unsymmetrical and pecu- 
“tae fering of 3 and M, in both front and hind wings. 
_ Two species of Newrocordulia are known. The venational dif- 
4 ference between them is slight, consisting of a greater number 
of antenodals in both front and hind wings in yamaskanensis 
__ a§ compared with obsoleta and scarcely definable differences in 
the form of the anal loop (differences in the form of the two 
_ distal angles and the direction of the distal side with reference 
to the long axis of the wing). Some of the venational differ- 
_  _@nces between the two species of Neurocordulia and Platy- 
_ ¢ordulia xanthosoma n. sp. are discussed below. The denser 
_ reticulation of Platycordulia is a striking character, recognized 
_ at once by the increased number of rows of cells between the 
__ sectors at a relatively proximal position in the wing. Type of 
Platycordulia: P. xanthosoma, n. sp. 
" ©The name refers to the broadened anal loop in the hind wing. 
ia est 
