410 Mr. R. M'Lachlan on some Odonata 



with blackish hairs, with a black T-spot, the top of which is 

 thickened in the middle, the tail dilated into a broad, nearly 

 equilateral triangle, the base of which extends nearly to the 

 outer angles of the front ; vesicle with two yellowish or bluish 

 spots ; eyes connected in a long space ; occiput very small, 

 yellowish or brownish ; back of head black. Thorax green 

 above, brown on the sides, interalar area spotted with greenish 

 white ; no antelmmeral or humeral bands, but on the sides 

 there is a rather narrow oblique greenish-yellow band under 

 each wing, not extending to the legs. Legs black; the coxae 

 and trochanters and the anterior femora beneath at the base 

 reddish. Abdomen slender, inflated at base and constricted 

 afterwards ; oreilettes small, acute, the apex incurved ; when 

 adult the general colour is blackish brown, paler at the base ; 

 on the sides the apex of segment 1 and base of segment 2 

 are occupied by a greenish-yellow transverse band divided by 

 the black suture ; there are indications of pale apical and 

 subapical spots on segments 4 to 7 ; above there is a large 

 and nearly round median pale spot on each side of 10 and an 

 apical spot on 7 to 9 (a less mature male shows a whitish 

 lateral band on segments 1 and 2 and half of 3, and a small 

 dorsal spot on each side of the false suture on segments 2 to 7, 

 the apical spots less distinct) ; tenth segment witli a median 

 dorsal carina, which near its base is elevated into a strong 

 triangular black tooth, with a tubercle placed in a fovea on 

 either side of it ; superior appendages (5 millim.) as long as 

 the ninth and tenth segments united, black, slightly curved 

 and narrowed at the base internally, the inner edge forming 

 a gradual curve to the apex, which is narrower than the base, 

 acute, and curved downward ; there is a strong median carina 

 from base to apex, dilating almost suddenly at the com- 

 mencement of the apical third, the internal edge fringed with 

 long hairs ; inferior appendages more than one half shorter, 

 elongately triangular, slightly notched at tip, curved upward, 

 brownish above. 



Wings hyaline; pterostigma very small (3 millim.), 

 ochreous, surmounting 2^ cellules ; membranule conspicuous, 

 smoky black, with whitish base ; nodal sector suddenly 

 elevated under the pterostigma; subnodal sector furcating 

 before the level of the pterostigma, 3 rows and 5 marginal 

 cellules between its branches ; 3 or 4 rows of cellules between 

 the subnodal and the interposed sector at the widest part ; 

 one row of cellules between the sectors of the triangle (more 

 towards the apex) in the anterior, two rows and afterwards 

 one in the posterior; no basal subcostal nervule; 15 to 17 



