BY ARTHUR WHITE. 140 



Subfamily Leptogastrinse. 



This subfamily, which is nearly allied to the Doi^ypo- 

 rjoiiince, is represented in the Australian Region by the 

 single genus Leptuyaster. 



27. Leptogaster, Meig. 

 (fTonypes, Latr.) 



Extremely slender elongated flies, with long hind legs, 

 and greatly elongated tarsal claws. 



Head wider than the thorax. Antennae placed high, 

 making the front short, the first and second joints very 

 short, and of about equal length, the third longer than 

 the first two together, and terminated by an arista-like 

 style. Moustache scanty, face long, and broader than 

 the front. Thorax somewhat arched and nearly bare; 

 two presutural and two supraalar bristles present. Abdo- 

 men very long and thin. Legs long and thin, the hind 

 pair much elongated; tarsal claws greatly enlarged. 

 Wing small, and always shorter than the abdomen, the 

 hind-angle quite sloped away, and the alula wanting. 



The species belonging to this genus are, with the pos- 

 sible exception of the genus Xeoitainus, the most diffi- 

 cult to identify of any of the Australian Asilidae. The 

 different species resemble one another very closely, and 

 furtheir difficulty is caused by the different appearance of 

 the two sexes, the female being usually very much the 

 larger. After examining a considerable number of species 

 from different parts of Australia, I have come to the con- 

 clusion that some of the characters usually relied upon for 

 distinguishing the different species are really of little 

 value. This applies particularly to the colouring of the 

 thorax and the position of the cross-vein closing the second 

 basal cell, characters that vary very much in the same 

 species. The only characters that seem to me of general 

 use are the colouring of the legs, the relative length of 

 the wings, and the shape of the second submarginal cell 

 (the space enclosed within the cubital fork), which may 

 be either slightly contracted towards the wing margin 

 or else wide open without any sign of contraction. In a 

 former paper, "New Australian Asilidae" (Pap. and Proc. 

 Roy. Soc. Tasm., 1913\ I gave a table of the various 

 known Australian species. Since then I have had the 

 opportunity of examining Walker's type of L. pedaniu>> 

 in the British Museum collection, which Miss Ricardo 

 states is the same species as Macquart's L. geniculata, and 

 I find that this species is apparently identical with L. 

 antipoda, Birjot. The species, therefore, given in my list 



