80 Records of the Indian Museum. [Voy. XVIII, 
AGRIONINAE. 
Genus Ischnura. 
I, elegans, Van der Lind, 
—= rtd ‘ —_ Three females, all differing in their colour 
scheme; this due partly to a teneral condition and partly due to 
the polychroism customary in this species. I have compared these 
with a series from Mesopotamia where the insect is very common 
and find that teneral forms are usually of a bright orange colour, 
especially as to the thorax. The orange pigment is soon absorbed 
and replaced by a greenish-yellow. Progressively with the absorb- 
tion of the yellow pigment, blue is laid down, so that a series of 
forms is met with, passing from orange and yellow, through green 
to blue. Pari-passu with this, black pigment is deposited until it 
largely obscures the ground colour. Thus the eye-spots are often 
absent in the very early stage, being replaced by a broad orange 
fascia which soon changes through yellow and green, to blue, the 
change beginning from the frout and extending backwards. At 
the same time, the black fascia which crosses the vertex, extends 
backwards and gradually laps round the area which is eventually 
to form the eye-spot. Evidence of this may actually be seen in 
the specimens quoted. The humeral fascia, usually found in this 
species, is unenclosed in all three specimens, but two small, black 
spots on the sides indicate the genesis of a posthumeral stripe. 
In one specimen, the second abdominal segment bears a some- 
what quadrate, black spot on the dorsum which is absent in the 
other two. ‘This specimen is a bright orange colour and has the 
eye-spots fully developed. ‘There is no doubt that some speci- 
mens retain the original orange 
colouring throughout imaginal 
life. The other two specimens 
are orange and blue respectively 
but have no eye-spots nor the 
quadrate spot on the second ab- 
dominalsegment. All other mark- 
ings are the same as the first 
specimen. In my Mesopotamian 
specimens, a regular series gradu- 
ating from the one to the other 
may be seen so that there is no 
doubt that the insects are identi- 
cal. 
It is possible to divide up a 
number of Agrionine larvae in 
Fic. 1.—Mask of larva of Ischnura this small collection into two 
elegans * species. (The age of the larvae 
; varies somewhat widely). One 
of these forms closely resembles the larvae of Ischnura senegalensis 
but it is probably the larvae of J. elegans. ‘The mask (fig. 1) is long 
