62 MEMOIRS OF THE QUEENSLAND MUSEUM. 



Frontal prolongation of head short and stout, yellowish; palpi brown, 

 the last segment about equal to the basal three taken together. Antennae shorter 

 than the palpi, the scape yellow, the flagelluni dark brown ; flagellar segments 

 beyond the third slender, cylindrical. Head light yellow ; vertical tubercle low. 



IMesonotal prasscutum light yellow, with the three usual stripes more 

 reddish yellow ; remainder of the mesonotum pale yellow ; an indistinct, capillary, 

 median brown line. Pleura yellow. Halteres pale brown, the knobs darker. 

 Legs with the coxs and trochanters light yellow; femora yellow, the tips 

 narrowly and indistinctly infuscated; tibiai and tarsi brown. Wings greyish 

 yellow, the costal and subcostal cells rich brownish yellow; stigma yellowish 

 brown ; veins brown. Venation : Es scarcely longer than B2-{-3 ; 118 long, parallel 

 to is'4+5 except at the tip ; petiole of cell 311 variable in length, from as long 

 as m to entirely lacking, cell Ml being short-petiolate to sessile ; m-cu punctiform. 



Abdomen yellow, the tergites with three brown stripes, the median stripe 

 very broad and conspicuous; segments 7 and 8 chestnut brown; hypopygium 

 yellow, only the ninth tergite brown ; sternites yellow. Male hypopygium with 

 the ninth segment twisted around nearly one-half so that the ninth tergite 

 occupies a ventro-lateral position; this latter is large and tumid, with a broad 

 U-shaped median notch, the margins very thick, the conspicuous lateral lobes 

 thus formed stout-triangular. The pleural appendages are two in number, the 

 dorsal one (nearest the tergite though actually ventral in position) a small 

 blackened blade with the inner edge conspicuously serrate ; the ventral appendage 

 is larger, pale, flattened, gradually dilated distally, the apical margin set with 

 about fourteen blackened spicules of which the four inner are isolated from one 

 another, the remaining one confluent in a slightly curved row. Ovipositor with 

 the valves short and fleshy as in the genus. 



Habitat: Queensland. 



llolotype, S , Brisbane, July 1, 1913 (H. Hacker). 



AUotopotype, $ . 



Paratopotypes, 18 (?9 's, July 1 (1913) and May 23 (1916) 



Type in the collection of the Queensland Museum. 



Macromastix tortilis is readily told from the other described species of the 

 genus by its light-yellow colour, the trilineate abdomen, and especially the large, 

 twisted male hypopygium. 



MACROMASTIX HACKERI sp. n. 



Antenme short ; general colouration yellow ; wings brownish yellow, the 

 costal margin more saturated ; stigma darker brown ; cell 2nd A very narrow ; 

 male hypopygium semi-inverted, the ninth tergite pale ; ninth sterno-pleurite 

 with a pencil of about seven powerful bristles near the dorso-caudal angle. 



Male. — Length, about 11 mm.; wing, 12-5 mm. 



Generally similar to M. tortilis. 



