iqig.] F. F. Laidi.aw : Indian Dragon/lies. 187 



Aciagrion tillyardi, sp, nov. 



3 6 <S ' ^ ?' Cheerapunji, Assam. 



Length of hind-wing cf ly^ mm., 2 I7'5 mm.; of abdomen, 

 cf 24*5 mm., 9 22"5 mm. 



Male. 



Head. — Lower surfaces yellowish-white. Upper lip dark 

 brown, fading to black at the base. Ante- and post-clypeus black. 

 Frons gray-blue to a point just above the base of antennae. First 

 joint of antennae gray-blue, the rest black. The remainder of the 

 anterior and upper surface of the head black, with a linear 

 gray-blue post-ocular mark on either side, joined by a fine, trans- 

 verse line of the same colour across the occiput. Posterior surface 

 black. Upper pole of eyes black, the remainder olive-gray, with 

 indications of a narrow, dark zone a little distance below the black 

 pole. 



Prothorax. — Metallic black above, under surfaces 3^ellowish- 

 white. 



Thorax. — Dorsal surface metallic black, with a pair of narrow 

 gray-blue ante-humeral bands; sides gray-olive, paler beneath. 



Abdomen. — Metallic black above, greenish- white below ; a very 

 fine apical ring of greenish-white, incomplete in the mid-dorsal 

 line, on segments 4-6. vSegmerits 9-10 gray-blue, 10 metallic 

 black; its dorsal posterior border emarginate. 



Anal appendages. — Black; upper pair about one half the 

 length of the loth segment, their upper and lower margins parallel 

 and equal in length, the posterior m.argin slightly concave ; lower 

 pair much shorter, conical and directed upwards. 



Legs. — Grayish- white. The posterior surfaces of the femora, 

 the articulations and spines black. 



Venation. — Pterostigmata brownish-black ; on the fore-wing 

 covering one cell, on the hinder wing about half a cell. Twelve 

 antenodal costal nerves. 



Female. 



There is a distinct enlargement of the abdomen from segments 

 7-10. Colouring as in the male with the following exceptions : — (i) 

 the upper lip is of a paler brown and (ii) segments 8 and 9, like the 

 rest of the abdominal segments, are black above. 



The posterior margin of the prothorax is in both sexes regu- 

 larly convex. 



Types a' and 9 will be returned to the Indian Museum. 



Genus Ceriagrion, Selys, 



Until about five years ago only a small number of species 

 were recognized as belonging to this genus. Within that period, 

 however, a considerable number of new species have been dis- 



