NO. 1571, DnAGONFLlES OF BURMA AND BIAM— WILLIAMSON. 309 



0. histrigatus Hagen. Described from India. (The male described 

 by De Selys in his wSecond Addition to the Synopsis des Gomphines 

 is not certainly histrigatus, and the second female described in the 

 Mon. des Gomphines as histrigatus is m-flavum."') Recorded from 

 Anam l)y Martin. Abdomen 30 nnn. ; hind wing- 33-34 mm. ; male 

 superior abdominal appendages twice as long as 10, turned down- 

 ward at apex; inferior appendage slightly shorter, in profile with 

 2 teeth, one at the first third, the other at the second third; female 

 vulvar lamina half as long as 9, divided at apex into two points. 



0. camelus Martin. Tonkin and Anam. Abdomen 50 mm.; 

 male abdominal appendages similar to hiforceps, but larger, the 

 branches of the inferior not separated at base; female described 

 as similar to hiforceps, but vulvar- lamina and occipital ])late not 

 mentioned. 



0. cerastis De Selys. India and Nepal. Abdomen 40-43 mm.; 

 hind wing 34-37 mm.; male appendages not known; female vulvar 

 lamina small, short, one-fourth the length of 9, notched for one-half its 

 length; female occipital plate with two median spines. 



0. circularis De Selys. North Burma. Abdomen 41 mm.; hind 

 wing, male 32 mm. ; female 38 mm. ; male sui>erior abdominal 

 appendages equal in length to 9 + 10, curved toward each other and 

 slightly downward, the apex beneath emarginate; inferior appendage 

 destroyed; female \T,ilvar lamina di\'ided into two conical contiguous 

 tubercles. 



0. frontalis De Selys. Described from a teneral female from India. 

 Abdomen 29 mm. ; hind wing 25 mm. ; vulvar lamina half as long as 

 9, lanceolate, the apex divided. 



0. geometricus De Haan. Java. Abdomen 36-37 mm.; hind 

 wing 29-31 mm.; male superior abdominal appendages twice as long- 

 as 10, curved toward each other and apically downward; inferior 

 appendage little shorter, curved strongly upward, and bearing a tooth 

 near the base; female vulvar lamina very short, its apex broadly 

 emarginate. 



0. grammicus Rambur. India. Abdomen 37-39 mm.; hind 

 wing 30 mm.; male superior appendages as long as 9 + 10, in profile 

 strongly curved, the apex flattened into a horizontal, almost bifid 

 plate; inferior appendage a little shorter, enlarged and flattened 

 basally, then curving abruptly upward in 2 slender contiguous 

 branches. 



0. inscriptus Hagen. Known only from the female from Java. 

 Abdomen 36 mm. ; hind wing 32 mm. ; vulvar lamina short and 

 wide, the apex truncated and emarginate. 



0. lineatus De Selys. India and Nepal. Abdomen 33-35 mm.; 

 hind wing 27 mm. ; male superior appendages almost as long as 9 + 10, 



aCauseries Odon, VII, 1894, p. 170. 



