258 DIXID^E. 



rather elongate ; tibiae without spurs. Wings comparatively 

 broad and large, bare of hairs, veins very distinct. No discal cell ; 

 four posterior cells ; the 2nd longitudinal vein forked, the costa 

 not terminating at the wing-tip. 



The venation is fully described under the generic description of 

 Diana, the only genus of the family. 



The habitat of the DIXID^E is moist places in woods, or near the 

 mountain-streams in which the larvae live. Wiunertz records 

 seeing them in considerable numbers performing aerial dances. 



The peculiar venation of this family, added to the very filiform 

 nature of the antennae, so that exact discrimination of the joints is 

 impossible, renders the members of it at once recognisable ; and 

 by these characters taken together it is at once separated from all 

 other families in the whole of the Diptera. 



Genus DIXA, %. 

 Dixa, Meigen, Syst. Beschr. i, p. 216 (1818). 



GENOTYPE, Dixa maculata, Mg. 



Head somewhat rounded. Eyes round, frons wide, eyes con- 

 tiguous or sub-contiguous below ; no ocelli. Proboscis at the end 

 of a short snout, distinct but not conspicuous. Palpi of four joints. 

 Antennae with the two scapal joints much larger than those of the 

 flagellum, the basal one sometimes so short as to be easily over- 

 looked. Flagellum of an uncertain number of joints, being so 

 fragile and hair-like towards its tip that it is impossible to dis- 

 tinguish the exact number.* Thorax highly arched, sub-gibbous 

 in some species. No transverse suture. Scutellum transverse, 

 metanotum arched. Abdomen moderately long, of seven or eight 

 segments, linear, shortly pubescent. Genitalia of male of moderate 

 size, distinct, somewhat clubbed. In the female the abdomen is 

 slightly widened before the tip, the ovipositor shortly pointed. 

 Legs long and slender ; coxae rather elongate ; tibiae without spurs 

 at the tip. Wings comparatively large and broad. The auxiliary 

 vein ends just before the middle of the wing; tlie 1st longitudinal 

 vein runs close to and parallel with the costa, folloiving it round the 

 wing nearly to the apex. The 2nd longitudinal vein begins beyond 

 the middle of the wing at a very wide angle, the first part 

 of the praefurca being perfectly straight and moderately long ; it 

 then takes at an acute angle 'a wide upward sweep, this second 

 section being longer than the first ; the vein then forks, the vein- 

 lets converging together towards the wing-tip. The 3rd vein 



* In the five Oriental species herein treated of, at least twelve joints are 

 visible (without counting the apical portion of the flagellum), all minutely but 

 very closely pubescent, so that I shall expect the exact number ultimately to 

 prove to be fourteen. 



