96 REVISION OF THE STKATlOMYID.E OF AUSTRALIA, 



about the same lengtli as first and second together, thickened, 

 annulated, and provided with a long, thread-like arista. Scu- 

 tellum with two spines. Abdomen about the length of head 

 and thorax together, constricted at base, and widening gradually 

 towards apex. Legs short and slender. Wings with the discal 

 cell small, four, posterior veins all incomplete and indistinct, 

 fourth arising from the second, basal cell. 



Of this genus, only one species has been described, but a 

 second species, distinguished by the yellow, scutellar spines, is 

 represented by a single specimen, in the collection of the Mel- 

 bourne Museum. 



ACANTHASARGUS PALUSTRIS White. 



Thorax and scutellum dull black, the latter with two, long, 

 black, marginal spines; abdomen purple-black; legs yellow, the 

 posterior tibiae frequently with a dark ring; tarsi yellow or 

 brownish; wings tinged with brown, and with a brown stigma, 

 which is distinct in the male, indistinct in the female. Lentrth, 

 (J$, 6 mm. 



Uab. — Tasmania. 



This species frequents rock-pools in the beds of mountain- 

 streams. It occurred not uncommonly in the early summer of 

 1914, but is usually scarce. Specimens will be found in the 

 collection of the Melbourne Museum. 



Subfamily PACHYGASTRIN.E. 



In this subfamily, the wings possess only three, posterior 

 veins, which all arise from the discal cell; the antennse bear a 

 long, thread-like arista. The Australian species are small, black 

 dies, with a short, ovate abdomen. 



Table of tht Aiixtraliaii, Genera of Pac/ipya.sf)-inti'. 



1 . Scutellum rounded PACHYOASTiiK Mei^'. 



2. Seutellum piodueed liaekwardn in a spine-like prolongation 



LONCHEGASTEK White. 



IT.Pachygaster Meig. 



Eyes bare, touching in the male, widely separated in the 

 female; antennae short, third joint orbicular, with four, slight 



