TWO NEW SPECIES OF THE GENUS ISCHNURA, 237 



Thorax black dorsally as far as the first lateral suture, with a pair 

 of blue antehumeral bands, which are rather broad ; sides blue, under 

 surface pale. 



Abdomen blue; segments one to seven with a black dorsal 

 longitudinal band and black articulations, eight, nine and ten 

 entirely blue. The black band on three to six is narrow for the 

 greater part of its length ; at its posterior sixth it widens slightly, 

 so as to form a diamond-shaped mark, narrowing again to join the 

 black articular ring. Tubercles of ten rather prominent. 



Legs white, small ; femora with a narrow black band posteriorly, 

 spines black. 



Anal appendages. Upper pair black ; lower pair white, their apex 

 with a fine black point. In profile the upper pair are blunt and 

 curved downwards ; the lower pair are a little longer, conical, directed 

 upwards. When looked at directly from behind their appearance is 

 as shown in the text-figure. Above them lies the square hollow 

 projection formed by the tubercles of segment ten. The upper 

 appendages show as a pair of crescentic structures, their concavities 

 lying to their inner sides. That part of the appendage which is 

 visible in profile is here seen as a small projection directed back- 

 wards, rising from the margin of each of the upper pair. The 

 lower pair have each a small dark apical projection approximated 

 to the lower margin of the upper pair, though extending backward 

 beyond them, and to be seen in profile. 



The species may be characterized briefly as follows : — 



A very small Ischnura, with feebly petiolated wings ; the ptero- 

 stigmata of all four wings similar and unicolorous. Posterior margin 

 of prothorax not lobed. Colouring blue wuth black marks, segments 

 eight, nine, and ten entirely blue ; postocular spots linear, confluent. 



The smaller of these two species, I. immsi, approaches 

 Agriocnemis very closely in the characters of its venation,, the 

 small extent of the petiolation of the wing being very marked. 

 On the other hand, whilst the arculus lies in line with the second 

 antenodal nerve in this species, in I. gangetica it usually lies 

 beyond the level of that nerve (though it is apparently somewhat 

 variable in position ; and in this respect I. gangetica also 

 approximates to Agriocnemis). It is worthy of remark that in 

 I. gangetica the strong downwardly directed spur of the superior 

 anal appendage recalls strongly that found in many species of 

 Argiocnemis. The whitish patches occurring on these appendages 

 are possibly " recognition marks." When the appendages are 

 divaricated, these marks may be conspicuous in the living 

 insect. One of the specimens has died with the appendages 

 in this position. Compare Tillyard's note on the male of 

 Hemiphlebia mirabilis, de Selys, and his remarks on the position 

 of Ischnura and Agriocnemis amongst the Agrioninse (Proc. Linn. 

 Soc. N.S. Wales, 1912, vol. xxxvii. pp. 443-464). 



The type specimens will be returned to the Indian Forest 

 Eesearch Institute. 



Uffculme, Devon, July, 1913. 



