640 ON SOME REMARKABLE AUSTRALIAN LIBELLULIN^E, 



one cross-nervule near its middle, another nearer the arculus, and 

 a third arising from base of arculus so as to form a small sub- 

 triangle; hypertrigonal space with 34 cells in forewing, 1-2 in 



hindwing. Nodal Indicator 

 shining jet black, except labium 



25-26 16-17 

 15-16 18-19 



Head: all parts 

 dark brown; front 



and clypeus hairy; vertex a large bifid tubercle, hairy, standing 

 up high and carrying two conspicuous spikes or horns; front ocellus 

 pale, transparent; other two smaller, brownish; antennce 4 mm., 

 slender, black. Thorax deep black all over, some brown hairs 

 on breast. Legs black with short spines. Abdomen rather 

 short and stout, 4 slightly narrower than 2-3, 2-4 rounded, 5-9 

 triangular in section, 8-10 narrower than the rest : colour jet 

 black : 2-3 with supplementary carina. Appendages: superior 

 2mm., separated at bases, undulating sublanceolate, hairy, pointed, 

 black; inferior 1*3 mm., broad subtriangular, slightly hollowed 

 out above, very dark brown. 



ffab. — Cooktown, N.Q. A single male in magnificent condition 

 taken on a billabong near the Annan River on Dec. 29th, 1907. 

 Its flight is slow and majestic, and it is fond of settling on pro- 

 minent twigs or branches overhanging the water. 



This magnificent insect is closely allied to C. gigantea Br., from 

 which it can be at once distinguished as follows : — 



(a) The opaque portion of the wings in G. gigantea extends 

 considerably beyond the nodus. 



(b) The colouration of C. gigantea, both on body and wings, is 

 rich brown. Mr. Laidlaw, who has seen this insect in the Malay 

 Peninsula at Kwala Aring, says : — " It haunts the same localities 

 as Neurothemis stigmatizans, which resembles it very closely in 

 colour, though, of course, much smaller." 



It is quite possible that C. Othello arose as a differentiation 

 from the parent stock C. gigantea, which does not occur in Aus- 

 tralia. Note the intensification and contraction of the opaque 

 pigment of the wings. This tendency carried to its fullest extent 

 can best be seen by comparing Neurothemis stigmatizans with N. 

 oligoneura. Compare with these two species C. gigantea and C. 

 Othello, and one feels that the same tendency is at work here, 



