270 REVISION OF THE THYNNID^ OF AUSTRALIA, I., 



curled as in I'achynomyia. The head beneath concave, but not 

 nearly as widely so as in Tachynomyia. Maxillary palpi with 

 the three apical joints filiform and much elongated as in Aelurus, 

 the basal joint very short. Labium rather short, labial palpi 

 rather stout, the basal joint the longest, without hairs at the 

 apex. No hairs on the labium. Labrum narrow, rounded 

 anteriorly and ciliated, rather long and slightly narrowed to the 

 base. The galea of the maxilla shows an obscure dividing line. 

 The abdomen is short, petiolate; the hypopygium has a spine on 

 each side near the base, and is produced either narrowly or tri- 

 angularly to the base of the apical spine. The third cubital cell 

 is long and receives the second recurrent nervure at about one- 

 third of the distance from the base to the apex. The claspers are 

 very long and slender. 



9. Head flat, quadrate, broader than the prothorax, the max- 

 illary palpi (according to Erichson) six-jointed; the mandibles 

 not bidentate. The prothorax is deeply excavated in the known 

 species, the median segments rather short, and the tarsal ungues 

 simple. The pygidium varies a good deal. 



Type A. bicolor Erichs. 



Key to the Species of Ariphron. 

 ^ ^ . i. Antennae bright orange. 



A. Wholly black. 



a. Median segment coarsely rugulose. A. petiolafiis Sm. 



b. Median segment shining, with a few shallow punctures. 



A. vagulus, n.sp. 



B. Black and ferruginous. 



a. Legs and abdomen, except segments 4-5, ferruginous. 



A. rigidulus, n.sp. 

 ii. Antennae black. 



A. Wholly black. 



a. Wings fusco- violaceous. A. hospes, n.sp. 



b. Wings fusco-hyaline. 



a^. Median segment punctured. A. blandulus, n.sp. 



62. Median segment smooth. A. rixosus Sm. 



c. Wings hyaline, iridescent. A. nudulu'^, n.sp. 



B. Abdomen and legs at least ferruginous or testaceous. 



a. Margins of prothorax yellow, abdomen and legs ferruginous. 



A. tryphonoides Sm. 



b. Wholly testaceous. .4, pallididus, n.sp. 



