362 EUMENID^. 



a'. Second abdominal segment with a lateral 

 free round spot at base, yellow. 

 o*. IJase of 1st abdominal segment red. 



a^. Abdomen petiolate O. miniatus, p. 366. 



h^. Abdomen not petiolate 0. diffinis, p. 366. 



h-. Base of 1st abdominal segment black, 

 a^, A lateral round yellow spot at base 

 of 1st abdominal segment. 

 «'. Median segment rounded pos- 

 teriorly O. fraterniis, p. 366. 



6'. Median segment emarginate pos- 

 teriorly O. conjluentus, p. 367. 



b^. No lateral yellow spot at base of 

 1st segment. 

 «*. First abdominal segment much 



narrowed, subpetiolate O.fragilis, p. 367. 



b^. First abdominal segment not nar- 

 rowed, broader tlian long. 

 «'. Apical margins of abdominal 

 segments 1-5 with complete 

 transverse yellow bands 



above O. multipictus, p. 368. 



b^. Apical margins of 1st and 2nd 



abdominal segments only with 



complete transverse yellow 



bands above. 



a^. Head, thorax, and basal three 



segments of the abdomen 



coarsely punctured O. ceylonicus, p. 368. 



6", Head, thorax, and abdomen 



with much finer punctures. O. bipustulatus, 

 b'. Second abdominal segment with the [p. 309. 



yellow transverse band at its apical 

 margin widening laterally and j oining 

 on to the lateral yellow spot at its 

 base. 

 a~. Head emarginate posteriorly, cheeks 



not much developed O. ovaUs, p. 369. 



6^. Head transverse posteriorly, cheeks 



considerably developed O. guttatus, p. 370. 



c' . Second abdominal segment without a 

 3'ellow lateral spot. 

 a^. Median segment deeply emarginate 

 posteriorly, the sides produced back- 

 wards O.Jistulosus, p. 370. 



b"^. Median segment not emarginate pos- 

 teriorly. 

 a^. Second abdominal segment subtu- 

 berculate near the base, and on 

 each side near the margin above . O. humbertiajius, 

 P. Second abdominal segment not tu- [p. 371. 



berculate above. 

 a*. Third abdominal segment with a 

 transvei'se yellow fascia on the 

 middle of its posterior margin 

 above O. burmanicus, p. 371. 



