410 Records of the Indian Museum. [Voi,. XXIV, 



yellow. Length of abdomen 29 mm., of hinder-wing 25 mm. 

 From de Selys account I should imagine that the vulvar apparatus 

 of the female did not show the remarkable arrangement found in 

 the female described above from the Garo Hills. 



Onychogomphus M-flavum Selys. 



1 3. Darjiling Dist., 1-3000 ft., May, 1912. Lord Carmichael's collection. 



(cc/1319). 

 1?. Gopaldhara, Darjiling district, 1914. H. Stevens. 



The synonymy of this species is somewhat obscure. I have no 

 doubt whatever but that the female specimen before me is properly 

 ref erred to the Selysian species. The remarkable long vulvar scale, 

 reaching to the apex of the abdomen is sufficient to make the 

 determination certain, and the agreement in colouring is precise. 



The male is I believe unquestionably conspecific with the 

 female, it differs only in having the costal-vein lined with yellow as 

 far as the nodus. It is immature and badly crushed. I believe 

 the colouring of the costal vein may well be lost in more adult 

 specimens and need not be regarded as a specific character. 



A second, more serious difficulty lies in the fact that the male 

 appears identical with that described by de Selys for 0. bistrigatus 

 (Selys) and figured by Hagen as such in the monograph. This is due 

 to the fact, as I regard it, that the specimen figured in the 

 monograph, and the male described in the second additions to 

 synopsis are not conspecific with the type-specimens of 0. bistrigatus, 

 but are really examples of 0, M-flavum, as is also the adult female 

 (imperfect) noted in the monograph, in the Vienna Museum. 



Hence in my opinion 0. bistrigatus remains known only from the 

 type female from ' India.' The figure of the occiput of the female 

 given in the monograph would appear to have been drawn from the 

 Vienna specimen of M-flavum as it shows none of the ' dentellures ' 

 described for 0. bistrigatus. 



Male. Dorsal stripes of synthorax meeting mesothoracic 

 collar, mid-dorsal carina marked with yellow for its anterior half. 

 Juxta-humeral stripes complete. Sides of thorax yellow with 

 narrow black bands on the lateral sutures. 



Abdomen largely black, with basal rings of yellow, constricted 

 mid-dorsally, on segments 3-6; and a mid-dorsal yellow mark on 

 each of the same segments. 



Basal two-thirds of the seventh segment yellow, distal third 

 black. Segments 8, 9 yellow at the sides, dark dorsally, 10 yellow 

 or light brown margined with black. 



Anal appendages yellow, upper pair darker apically, the distal 

 third rather sharply angled downwards, and lancet-shaped. 

 Branches of lower appendage about two-thirds length of upper pair 

 contiguous and parallel, curved upwards, with stout dorsal tooth 

 at end of basal third, and smaller tooth at junction of middle 

 and distal thirds (exactly as in pi. i, fig. 3, Mon. Gomph.). Seg- 

 ments 8, 9 of abdomen, and distal half of 7 slightly dilated. 



