THE SUBFAMILY LIBELLULEN^. 275 



simply traversed and followed by 3-6 rows of cells, a supratriangular nervure rarely 

 present, subtriangular space consisting of 3-5 cells, sectors of the arculus distinctly 

 separated on the fore wings and stalked in the hind wings, gradually curved, lower 

 basal cell with one cross nervure, nodal and subnodal sectors continuous nnd nearly 

 straight, many of the cells bisected beyond the middle of the intermediate space ; 

 hind wings rather broader than the fore wings, with 5-6 antenodal and 8-10 postnodal 

 nervures, the first three or four of the latter not continuous, the triangle open or 

 traversed, sometimes by a forked nervure, and followed by 3-5 rows of cells, no supra- 

 triangular nervure, one cross nervure in the lower basal cell, sectors of the triangle 

 united at the base : anal appendages rather short. 



Type Libellula eponina, Dru. 



I have a little extended the characters of this genus in order to include in it Biplax 

 elisa of Hagen (placed in Leucorliinia by Brauer, but more correctly referred to Celi- 

 themis by Walsh) and a new species. Biplax amanda. Hag., and Libellula ornata, 

 Eamb., may also be included provisionally in Celithemis, though they are smaller and 

 the nervures less numerous than in the more typical species. 



Genus 18. Leucoehinia. 

 Brittinger, Sitzungsb. Akad. Wiss. Wien, math.-nat. Classe, i. p. 333 (1850) ; Brauer, Verb, zool.- 



bot. Ges. Wien, .xviii. p. 719 (1868). 

 Leucorhina, Brauer, 1. c. p. 368 (1868). 



Frontal tubercle rounded above ; eyes contiguous ; abdomen moderately slender, not 

 longer than the hind wings, the basal and sometimes also the terminal segments a 

 little thickened, segment 3 (sometimes also 2) transversely carinated, segment 8 not 

 perfoliate in the female, ptcrostigma short and broad, not more than twice as long as 

 broad; fore wings with 7-8 antenodal and 6-10 postnodal nervures, the last antenodal 

 nearly always continuous, the first three to five postnodals not so, cells of the costal 

 area simple, triangle rather wide, on a level with that of the hind wings, nearly always 

 traversed, no supratriangular nervures, subtriangular space consisting of from 1-3 

 cells, triangle followed by 2-4 cells, sectors of the arculus separated, or rising from a 

 very short stalk (distinctly stalked on the hind wings), gradually curved, lower basal 

 cell with one cross nervure, nodal and subnodal nervures continuous, the intermediate 

 cells bisected towards the hind margin ; hind wings broader than the fore wings, with 

 5-6 antenodal and 8-10 postnodal nervures, the first three or four postnodals not 

 continuous, triangle free, no supratriangular nervures, one cross nervure in the lower 

 basal cell, sectors of triangle united at base : anal appendages of the male rather short. 



Type Libellula albifrons, Burm. (This species is not before me, and I have had to 

 take the characters of the genus from L. pectoralis, Charp., dubia, Lind., rubicunda, 

 Linn., hudsonica, Selys, and intacta. Hag. ; the last species is somewhat aberrant, but I 

 have only been able to examine two bad specimens.) 



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