BY G. H. HARDY. 287 



or the Australian region, little assistance for determining them is to be found in 

 the works on the Asilidae of other countries. 



In this revision, primary characters only are dealt with and these group the 

 genera into convenient sections. The characters differentiating the genera within 

 these sections will be found under their respective generic headings. 



The exoskeleton shows differences of generic value in the characters dis- 

 cussed below. 



Antenncue. The antennae contain three joints and an appendage of one or 

 two vestiges of joints. These vestiges have been called the style and the first 

 may be absent; tlie second vestige is invariably indicated, often very minutely 

 so, and it is spine-like. 



A study of the antennae of the various genera of the Dasypogoninae has 

 convinced me that the first vestigial joint, which is sometimes long and con- 

 spicuous, should be called the fourth joint, and the second spine-like vestigial 

 joint should be called the fifth. 



If the fourth joint becomes obsolete, by being amalgamated with, or in any 

 other way indistinguishable from, the third, then the fifth joint will appear to 

 be on the third, usually in the form of a spine. 



Invariably the fifth joint is indicated ; either it is contained within a de- 

 pression on the extreme apex, as illustrated in Text-figures 3, 5, 6 and 7, or it 

 is contained within an apical incision placed dorsally and occurs either on the 

 fourth joint or on the third, as illustrated in Text-figjures 4 and 8 respectively. 

 Sometimes the fifth vestigial joint is obscure and difficult to find. 



Thorax. Two genera have a pair of spines on the thorax, one placed on 

 each side, a little above the wings. This character appears to be most impor- 

 tant, as the species which possess it also have an elongate neck and the wings 

 placed well beyond half the length of the thorax (Text-fig. 1); these cliaracters 

 give the species the very characteristic appearance they all possess. 



Legs. The anterior tibiae in some of the genera contain a spur at the apex. 

 This spur has been used to divide the genera into two groups, in one of which 

 the spur is missing, but in tliis paper the character is derogated to a position of 

 less importance. 



Wings. The venation is somewhat variable, even within a species, but in a 

 few genera the fourth posterior cell is closed considerably before the wing mar- 

 gin. In the remaining genera it is open, or at most closed on the wing margin. 

 The character appears to be important and is here placed second in value to 

 that of the thoracic spines. 



Key to the genera of the Dasypogoninae. 



1. Thorax with a pair of lateral spines, one placed on each side a little above 



the wings 2 



Thorax without such spines 3 



2 Antennae with a two-jointed style consisting of the fourth and fifth an- 



tennal joints Chrysopogo?! 



Antennae with a one-jointed style consisting of the fifth antenna! joint in 

 the form of a strongly developed apical spine Opseostlengis 



3. Wings with the fourth posterior cell closed considerably before the wing 



margin 4 



Wings with the fourth posterior cell open, or at most closed on the wing 

 margin • • 5 



