32 HYMENOPTERA. 



81. THYNNUS (AGRIOMYIA) SEXMACULATUS. B.M. 



Male. Length 5-J lines. Black: head and thorax closely 

 punctured and subopake; abdomen very smooth and shining; 

 legs ferruginous, with the coxse and trochanters black, and the 

 tarsi fuscous or fusco-ferruginous ; the head,, thorax, and legs 

 thinly covered with hoary pubescence. The anterior margin of 

 the clypeus and face, the mandibles, a narrow interrupted line 

 on the anterior margin of the prothorax, and an ovate macula 

 on each side of the second, third, and fourth segments of the 

 abdomen, white ; beneath, smooth, shining, and impunctate ; the 

 terminal segment of a broad lanceolate form, with a minute 

 tooth at its apex. 



Hab. Australia (Sydney). 



82. THYNNUS (AGRIOMYIA) BIDENTATUS. B.M. 

 Male. Length 4-J- lines. Black and shining: head closely 



punctured and thinly covered with cinereous pubescence ; the 

 clypeus, an ovate spot above each antenna, the mandibles, and 

 an abbreviated line behind the eyes, yellow ; a black line ex- 

 tending halfway down the clypeus ; the anterior margin of the 

 clypeus and the tips of the mandibles ferruginous. Thorax : a 

 broad stripe on the anterior and posterior margins of the pro- 

 thorax, a spot on the tegulae, a quadrate spot on the mesothorax, 

 an ovate one on the scutellum, the post-scutellum, an oblong 

 spot at the sides of the metathorax, a large spot beneath the 

 wings with a smaller one behind it, yellow ; the tibiae and tarsi 

 ferruginous ; a yellow spot at the apex of the anterior and inter- 

 mediate femora outside; the intermediate and posterior tarsi 

 dusky ; the wings hyaline, the nervures ferruginous. Abdomen : 

 the posterior margin of the segments broadly and deeply de- 

 pressed, each segment with a large subovate macula on each 

 side ; beneath roughly punctured, the second and three following 

 segments with a large yellow macula on each side, the fifth seg- 

 ment armed on each side with a long stout acute tooth which 

 curves backwards ; the apical segment lanceolate. 



Hab. Australia (Swan River). 



83. THYNNUS (AGRIOMYIA) COMBUSTUS. B.M. 

 Male. Length 4 lines. Black, with the abdomen red : the 



clypeus very much produced, ferruginous anteriorly and trun- 

 cate, the margins on each side of the truncation and a stripe on 

 the mandibles yellowish-white ; two minute white spots between 

 the antennae. The anterior margin of the prothorax with a 



