216 REVISION OF THE THYNNID.E OF AUSTRALIA, I., 



h. Head produced behind the eyes, very large. Epipygium 



narrowly rounded. R. rejlexus Sm. 



B. Prothorax not produced at the lateral angles. Smooth and 

 shining. 



a. Hypopygium without lateral spines. R. ker'fyafus Sm. 



b. Hypopygium strongly tridentate. /*. neptmms, n.sp. 



$ 2 . i. Head nearly square, with a very narrow sulca on each side, 

 reaching from the eye to the occiput. 



A. Thorax and median segment without lateral depressions. 



a. Median segment not concavely hollowed. 



a-. Epipygium broad at the base, shortly and bluntly pro- 

 duced to the apex, with a slight median sulca at the 

 apex, 

 a^. Black, head with two large ochreous macula? on the 



front. R. unicolor Guer. 



h-^. Black, head with two large ferruginous macula? on the 

 front, mesothorax and median segment ferruginous. 



R. unicolor st. mandibularU Westw. 

 '•"^ Black, the metathorax and median segment ferruginous. 



R. unicolor st. ephippiger Guer. 

 b'^. Epipygium narrowly produced, with two subparallel longi- 

 tudinal carina? on the disc. 

 a^. First abdominal segment short, vertically truncate at the 



base. Thorax black. R. fuscipennis Sm. 



b^. First abdominal 'segment longer, narrowed to the base, 

 where it is concavely truncate. Thorax red. 



R. auric( ps, n.sp. 

 C-. Epipygium gradually narrowed to the apex. 

 a'-^. First abdominal segment produced above at the base 



over the apex of the median segment. R. grncilior, n.sp. 



b. Median segment concavely depressed from near the base. 



a'~. The depression of the median segment very slightly concave. 



a*. Prothorax fairly long. R. fulvipennis, n.sp. 



b'^. The depression of the median segment strongly concave. 



a^. Prothorax very short. R. approximatns, n.sp. 



B. Thorax or median segment with a depression on each side. 



a. Median segment with a very shallow depression on each side. 

 a~. Epipygium narrowly produced, with two subparallel 



carina? on the disc. R crasslpunctafu^, n.sp. 



/>■-. Prothorax with a deep depression on each side near the 



posterior margin. R. cmalis Westw. 



ii. The sulca? on the head enlarged into broad, shallow depressions. 

 A. Thorax without depressions. 



a. Pygidium simple. R. ktrigatus Sm. 



