Appendix 



above the base of the intermediate legs, yel- 

 low. Metathorax, black, with two yellow 

 spots behind and a larger one, on either side, 

 above the base of the hind-legs. The first 

 two spots are sometimes missing. 



Abdomen, brilliant black above and bare, 

 except at the base of the first segment, which 

 bristles with whitish hairs. All the segments 

 have a wavy transversal band, wider at the 

 sides than in the middle and nearer to the 

 hinder edge as the segment is farther back. 

 On the fifth segment, the yellow band touches 

 the hinder edge. Anal segment, yellow, 

 black at the root, covered all over the dorsal 

 surface with rusty-red papillae, forming a base 

 for bristles. A row of similar bristle-bear- 

 ing protuberances occupies also the hinder 

 edge of the fifth segment. Underneath, the 

 abdomen Is brilliant black, with a triangular 

 yellow patch on either side of the four inter- 

 mediary segments. 



Black hips; thighs, yellow in front, black 

 behind; yellow legs and tarsi. Transparent 

 wings. 



In the male, the chevron mark on the shield 



is narrower, or even entirely absent, in which 



case the face is all yellow. The bands on the 



abdomen are a very pale yellow, almost 



417 



