560 THEREVID^ 



Abdomen shining black at the base of the segments but otherwise 

 almost covered with the dull golden or ashy grey dust; basal segment 

 light brownish ashy grey ; third to sixth segments with narrow orange hind- 

 marginal hems of which the one on the third segment is broadest and the 

 one on the sixth segment narrowest ; the segments are broadly dull golden 

 in front of these orange hems and on most of the second segment, but the 

 fifth and sixth segments are slightly greyish golden with only the front margin 

 of each segment black ; in very good specimens the black basal ground colour 

 is hardly visible on the second and third segments because of the abundant 

 golden pubescence, though usually the middle of each segment is obscurely 

 blackish for about half or two-thirds of the length of the segment, or on 

 the third segment the basal third is left blackish and is rather abruptly 

 though vaguely widened at the middle for quite two-thirds of the length 

 of the segment ; the fourth segment has more than the basal third shining 

 black and this band slightly widened about the middle ; fifth segment with 

 a similar but narrower basal black band which is more conspicuously widened 

 about its middle ; sixth segment similar to the fifth but with the black 

 base narrower still ; in all these segments the basal black band is almost 

 equally wide over the sidemargins, though yellow dust (especially on the 

 sixth segment) may obscure the sides a little ; seventh and eighth segments 

 shining black, but the seventh segment with some pale dust about the 

 hind corners ; ovipositor with the usual circlet of shining dark red spines. 

 Pubescence depressed but abundant and dark golden on the two basal 

 segments, altogether shorter on the third segment, and less abundant on the 

 sicles and middle of the foremargin, and still less abundant on the fourth 

 segment ; basal segment with a conspicuous prashindmarginal fringe of 

 long pale hairs ; pubescence on the fourth, fifth, and sixth segments 

 shorter, stiffer, and more erect, usually all orange except for a few black 

 hairs- on the middle of the black base, and usually with notable erect orange 

 pubescence standing out from the sides, but less comjnonly this erect side 

 pubescence is considerably or even wholly black at the sicles of the sixth 

 segment and to a considerable extent on even the fifth segment ; on the 

 seventh segment the stiff erect pubescence is usually almost all black but 

 with a few yellow hairs intermixed about the basal corners and beneath 

 (but very distinct from the obvious yellow pubescence on this segment in 

 T. bipunctata), or rarely all this pubescence on the seventh segment may be 

 quite black ; eighth segment with similar short stiff erect black pubescence. 

 Belly dull yellowish grey or grey about the basal three segments, but slightly 

 browner and rather shining on the fourth, fifth, sixth, and especially seventh 

 segments ; second and third segments with fairly wide whitish yellow hind- 

 marginal hems, fourth and fifth segments with narrower hems, which are 

 in fact usually inconspicuous on the fifth (and sometimes sixth) segment ; 

 pubescence never dense, but rather erect and yellow, with a fairly conspicuous 

 orange fringe on the hindmargins of the fifth, sixth, and seventh segments, 

 and with rigid orange hairs about the hind corners of the seventh segment ; 

 eighth segment bright shining chestnut. 



Legs with light grey dust on all the femora and with some pale depressed 

 dorsal pubescence, but any pubescence behind or beneath the anterior femora 

 is rather short and inconspicuous ;_ coxal bristles as in the male but more 

 conspicuous on the posterior (especially middle) pairs ; bristles on the femora 

 and tibi93 almost as in the male. 



Wings and squamae as in the male but distinctly lighter, which gives the 

 latter a more yellowish tinge. Halteres brownish orange, with the base 

 of the knob darker and the stem paler. 



Length about 10-5 mm. 



This species varies very much in the male as to the greater or less 

 quantity of black hairs in the pubescence on the upper side of the abdomen 

 and on the anterior femora, and also in the quantity of black hairs on the 

 sides of the face ; the pale pubescence varies everywhere in tint of colour, 

 ranging on the thorax and especially on the abdomen from brownish 



