INDIAN DRAG ON FLIES, 



Gemis Hydrobasileus. 



65 



Fig. 57. — Wings of Hydrobasileus croceus to show neuration. 



Head relatively large ; eyes contiguous for a long distance ; forehead 

 prominent and rounded ; suture deep ; vesicle high and deeply notched. 



Frothorax with a small lobe which is hidden beneath the head. 



Thorax robust. Legs long and slim ; hind femora with a row of numerous 

 small but gradually lengthening spines ; mid femora with similar spines 

 but less numerous and rather wider spaced ; tibial spines fine, short and 

 numerous ; claw-hooks very robust, situated about the middle of claws. 

 Armature of the female very similar but the spines rather less numerous 

 and more widely spaced. 



Abdomen relatively short, the base dorso-ventrally dilated, the sides 

 much compressed, tapering from the base to the end. A transverse ridge on 

 the 4th segment. 



Wings very long and broad ; reticulation moderately close ; trigone in 

 the forewing about 3 cells distal to the line o.' the trigone in the hind ; 

 sectors of arc in forewing with a short fusion, in the hind a somewhat 

 longer one, the sectors running very close together at their origin ; arc 

 lying between the 1st and 2nd antenodals; antenodal nervures 12^ to 18^ 

 the final incomplete, the distance between the 1st two antenodals dis- 

 tinctly longer than that between those following : base of trigone in 

 the hindwing at the arc ; 1 cubital nervure to all wings ; no supplementary 

 nervures to the bridge ; 8th nervure from the anal angle of trigone ; tri- 

 gone in the forewing very long, with a very short costal side, traversed 

 once or twice ; trigone in the hindwing longer than usual, entire, the 

 distal side concave ; all hypertrigones entire ; subtrigone in the forewing 

 variable, with 8 to 8 ceRs, its outer angle a little obscure and tending to be 

 lost in the general reticulation ; 4th nervure strongly undulated ; 2 rows 

 of cells between 5 and 5« ; 8th nervure in the forewing moderately curved 

 and short ; the discoidal field contracted at the end due to an abrupt 

 curving of the 7th nervure towards the termen, the field usually beginning 

 with one or two rows of 4 cells and then continued as rows of 3 cells ; the 

 loop with a long body and short toe, its outer angle very obtuse and its 

 inner border often incomplete and lost in the general reticulation so that 

 the loop is open at the apex ; a distinct supplementary sector runs from 

 the angulation of the inner border of loop, which splits up the anal area 



