404 Records of the Indian Museum. [Vol. XXIV, 



in the British Museum, M. coquatus Selys, and M. hageni Selys, 

 both appear to be derived from it. I,ike the last this section con- 

 tains ' xerophilous ' forms. 



Onychogomphus lineatus Selys. 



2<3'd , l 29$. Poona, May-Aug., 1918. F. C Fraser. 

 2(?d,2 9$. Chota Nagpur, July, August, 1915. E. d'Abreu. 

 1 <? (with larval exuviae). Pcradeniya, Ceylon, 1700 ft., 7-X-17. N. 

 Annandale. 



Probably a very common species. The presence or absence 

 of a row of small denticles on the posterior margin of the occiput 

 seems to be an individual character ; two of the females are with- 

 out the denticles, and one of the males (from Poona) has three 

 or four denticles unsymmetrically arranged in this position, the 

 other males lacking them altogether. It would be interesting to 

 study this character in series from different localities, and also to 

 determine how it is inherited. 



Young males have the last four segments of the abdomen 

 entirely yellow, with increasing age a black band develops on the 

 dorsum of these segments, and at the same time the colouring of 

 other parts of the body deepens, making the fully adult insect 

 differ considerably in appearance from younger specimens. 



0. lineatus seems to range over the Indian Peninsular but the 

 limits of its distribution to the north and east are not known. 



Possibly allied to this species are 0. reinwardtii Selys, from 

 Java and 0. capitatus Martin, from Celebes. 



0. lineatus is the only Gomphus I know of that shows a develop- 

 ment of the second abdominal segment resembling the ,f genital 

 lobes " of the Iyibellulidae. 



Section III, geometricus. 



Black markings on upper lip and head ; frons largely black. 

 Dorsal stripes of synthorax meeting mesothoracic collar to form a 

 pair of inverted 7-shaped marks. Antehumeral stripes interrupted 

 or represented by superior spot only. Segments 7 (distal half), 8 

 and 9 of abdomen dilated from side to side, the dilatation increas- 

 ing regularly to the distal end of 8. These segments black above. 



Upper pair of anal appendages orange or yellow in colour, well 

 separated at origin, regularly tapering, cylindrical, a little down- 

 curved. Lower appendage with its branches approximately equal 

 in length to the upper pair ; closely applied to one another for their 

 whole length, moderately upturned. 



Specially characteristic of this group is the combination of 

 inverted 7-shaped marks with a vestigial antehumeral band on the 

 dorsum of the synthorax. Only one other Indian species of 

 Onychogomphus, 0. annularis Selys, shows this feature in addition 

 to the species referred to the section. And as that species was 

 described from imperfect specimens, and remains very imperfectly 

 known, it is quite possible that it too may ultimately find its place 

 here. 



