312 PROCEEDINGS OF THE NATIONAL MUSEUM. vou xxxnr. 



hh. Segment 6 more than one-half black. 

 c. Black stripes on the 2 lateral thoracic sutvu'es confluent. 



d. Size very large, abdomen abont 50 mm cainchi.s 



dd. Size smaller. 



e. Abdominal s(»gments 8 and 9 ])l:ick; dorsal thoracic stripes very wide. 



thnmassoni 

 ee. Segments 8 or 9 or botli with lateral basal yellow spots. 



/. Segments 3-7 with basal one-fifth yellow viaclachlani 



Jf. Segments 3-6 with basal one-fourth, 7 with basal one-half yellow. 



smindersii 

 cc. Black stripes on the 2 lateral thoracic sutures not confluent for their entire 

 lengths. 



d. Face largely yellow, nasus yellow marked with black cirndaris 



dd. Face largely black, nasus black or black marked with yellow. 



e. Abdominal segments 8-10 all black annularis 



ee. Segments 8-10 black, 8 with lateral- l)asal yellow spots biforceps 



ee.e. Segments 8-10 with yellow laterally m-Jlavum. 



Four species of tlie genus are certainly known to occur in Burma: 

 a fifth species probably is an Onychogomphus. 



14. ONYCHOGOMPHUS SAUNDERSH De Selys. 



"Bhamo. Un couple en juillet et aout (Fea)." I have a single 

 male from Earnshaw. This is the onh Onychogomphus known from 

 Sumatra. 



Head largely black; upper lip with a basal spot on each side, 

 almost all rhinarium, a lateral spot on the nasus, and a band above 

 on the frons anteriorly yellow; female with black more restricted, 

 the yellow on the frons descending a little in front and upper lip 

 yellow with a black border. Pale antehumeral stripe reduced to a 

 line below and a spot above. Sides of thorax largely black, a yel- 

 low stripe on the mesepimeron and a wider one on the metepimeron. 

 Legs black, first femora with inner surface pale. 



15. ONYCHOGOMPHUS CIRCULARIS De Selys. 



^'Patrie: Nord de la Birmanie. Un couple uni([ue. (Coll. Mc- 

 Lachlan)." Recorded from Tonlvin by Martin. 



Face 3"ellow, black as follows: Upper lip bordered and traversed, 

 rhinarium margined, nasus at the center, and the suture between 

 nastis and frons. Antehumeral stripe reduced to a trace. Sides of 

 thorax yellow, with black stripes on the two lateral sutures. Femora 

 yellow, with brown and black markings. Abdomen black, varied 

 with yellow; 3-7 with 3'ellow basal rings, larger on .3 and 7; 3-5 

 with dorsal lanceolate spots; 8 with dorsal and lateral spots; 9 and 

 10 black. 



16. ONYCHOGOMPHUS ANNULARIS De Selys. 



^'Patrie: Le Nord de la Birmanie. Deux males (a abdomen 

 incomplet). Commimi(|ue par M. McLachlan." A female in my 

 collection from Earnshaw. 



