666 DIPTERA OF AUSTRALIA, 



IV. Imago. 



External structMre. 



Head small, above broader than long, lound when viewed 

 from the front, narrower than the thorax. Hypostoma and front 

 broad. Eyes reniforiu, bi'oader below than above, approaching 

 on the front or contiguous. Ocelli three, arranged iii a triangle 

 on the vertex, the lower one smaller than the upper two. 

 Proboscis short, thick, usually slightly projecting ; large 

 suctorial labelhi. Palpi prominent, incurved, four-jointed ; 

 first joint very small ; second and third joints nearly of 

 equal length, the former generally narrowed at the base, the 

 hitter sub-cylindrical or elliptical ; the foui'th joint slender,^ 

 elongate ; more or less densely covered with most microscopic 

 l»ubescence, generally sparingly setose, apparently never glabrous. 

 Antennae arcuated, projecting forward, generally short, 2--I-14- 

 joiuted ; the joints of the scapus almost bare, prominent, the first 

 joint cyathiform, cupuliform or sub-cylindrical, the second cya- 

 thiform ; the flagellar joints cylindrical or ovate, densely pubescent, 

 often verticillate-setose ; generally sub-sessile, the pedicels rarely 

 very distinct, sometimes sessile. Thorax ovate, gibbose, with 

 two or three longitudinal rows of setaceous-hairs, more or less 

 interspersed with short fine hairs ; the lateral margins between the 

 origin of the wings and the humeri generally with long setaceous 

 hairs, alho a few on the scutellum ; no transverse suture ; scu- 

 tellum small. Halteres * large, with microscopic pubeocence, 

 usually very sparingly setose ; altogether wanting in JEpidajms. 

 Legs long, frequently very long, slender. Coxse somewhat 

 elongate, except in Epidapui^, with a more or less spai'se seta- 

 ceous pubescence in front. Femora modex'ately robust, with a 

 shallow furrow on the inner side, covered with microscopic pubes- 

 cence, setose in front. Tibije and tarsi very densely covered 



*Winnert.z says, " Schwinger unbedeckt," but this is not the case even 

 though we may not recognize their often dense microscopic pubescence. 



