292 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXIII. 



L. f maculivertex De Selys. Burma. Abdomen, female 33 mm. ; 

 hind wing, female 31 mm.; antenodals, front wing 15; postnodals, 

 front wing 12; basal antenodal second series wanting. 



L. f nietneri Hagen. Ceylon, Burma, Tonkin. Abdomen, male 

 35 mm.; hind wing, male 30 mm.; antenodals, front wing 16-17; 

 postnodals, front wing 11-14; basal antenodal second series want- 

 ing; cubital space of front wing with 2 cross veins. 



L. iMvvus Kriiger. Sumatra. Abdomen without appendages, 

 male 27 mm., female 29.5 mm.; hind wing 21 mm.; antenodals, 

 front wing 14-15; postnodals, front wing 10-11; basal antenodal 

 second series wanting; between Mj_3 and M^ 3 cross veins in front 

 wing, 1 in hind wing. Kriiger's description of venation and legs 

 indicates that this is not a congener of semperi. 



L. semperi De Selys. Philippines, Borneo, Tonkin. Aljdomen, 

 male 39 mm.; hind wing, female 33 mm.; antenodals, front wing 

 15-17; hind wing 12; postnodals, front wing 12. (See figs. 17 and 18.) 



Fig. 17.— Wings of male Leptogomphus semperi from Borneo. 



The species may be grouped, according to the different characters, 

 as follows: 



1. Dorsal thoracic stripes isolated (jestroi, inclitus, lanshcrgci, nietneri 



Dorsal thoracic stripes joined below with the mesothoracic half collar. 



(jracilis'hiditns, helantanensis, 77}acHlivcrt('.v, parvus 

 Uncertain semperi 



2. Antehumeral yellow stripe present, complete gestroi, inclitns, lansbergei 



Antehumeral stripe interrupted, represented by one or more spots. 



(jraciUs, maculivertex, nietneri, parvus 

 Uncertain semperi, helantanensis 



3. Abdominal segments 3-7 with dorsal stripe only or all black. 



gestroi, helantanensis, maculivertex 

 At least segments 3-5 with lateral spots or rings. 



gracilis, incliius, lansbergei, nietneri, parvus, semperi 



