280 MR. W. F. KIEBr— A EEVISIOX OF 



simple, triangle moderate, free, on a level with that of the hind wings, followed by two 

 rows of cells, no supratriangular nervures, subtriangular space consisting of 1-3 cells, 

 sectors of the arculus stalked, the lower sector a little irregular towards the extremity, 

 lower basal cell with one cross nervure, nodal sector undulating at base, the subuodal 

 sector a little irregular towards the extremity, cells between the nodal and subnodal 

 sectors only bisected on the hind margin, lower sector of the triangle regularly zigzag, 

 subparallel to the upper ; hind wings a little broader than the fore wings, with 6 ante- 

 nodal and 6-7 postnodal nervures, the first two postnodals not continuous, triangle 

 free, followed by two rows of cells, or by two, one, two and three, no supratriangular 

 nervures, one cross nervure in the lower basal cell, sectors of the triangle united at the 

 base : anal appendages of male short, slender, a little depressed. 

 Type Perithemis duivenbodi, Brauer. 



Genus 27. Brachydiplax. 

 (Plate LIV. fig. 9.) 

 Brauer, Verb, zool.-bot. Ges. Wien, xviii. pp. 172, 368, 725 (18G8). 



Frontal tubercle rounded ; eyes contiguous in the middle ; abdomen as long or longer 

 than the hind wings, a little thickened at the base, and tapering gradually towards the 

 tip, segments 2 and 3 carinated, pterostigma moderate : fore wings with 6-7 antenodal 

 and 5-6 postnodal nervures, the first two postnodals not continuous, cells of the post- 

 costal area simple, triangle rather broad, free, followed by two rows of cells, no supra- 

 triangular nervure, subtriangular space consisting of 1-8 cells, if of two the lower 

 triangular portion is cut off by a curved nervure, sectors of the arculus stalked, lower 

 basal cell with one cross nervure, nodal sector undulating at base, the subnodal sector 

 and lower sector of the arculus a little irregular beyond the middle, cells between the 

 nodal and subnodal sectors only bisected on the hind margin ; hind wings a little 

 broader than the fore wings, with 5-6 antenodal and 5-6 postnodal nervures, the first 

 two postnodals not continuous, triangle free, the base only just beyond the arculus, 

 followed by a single row of cells (the first obliquely divided) and then by two or more, 

 no supratriangular nervure, one cross nervure in the lower basal cell, sectors of the 

 triangle united at the base ; legs armed with numerous slender spines : anal appendages 

 of the male rather short, depressed. 



Type Biplax denticauda, Brauer. 



As Brauer's type is not before me, I have characterized this genus from £. maria, 

 Selys, and a new species described below. 



Genus 28. Brachtjiesia, g. n. 

 Male. — Frontal tubercle large, indented, but hardly bifid at the extremity ; eyes 

 contiguous ; abdomen rather stout, much thickened at the base, and gradually tapering, 

 segments 2 and 3 carinated : wings and pterostigma moderate ; fore wings with 9 ante- 



