558 THEREVID^ 



(wliere the back of the head is widest in profile) about six strong black 

 bristly hairs are intermixed quite away from the eyes, and on the upper 

 part there is a postocular ciliation of about thirty longer black hairs ; the 

 black bristles behind the ocelli long ; vertex dull golden and bearing 

 moderate shorter black pubescence and with some inconspicuous pale hairs 

 between the ocelli. Eyes touching for about a quarter the distance between 

 the occiput and the antenna, but the part of contact nearer to the occiput 

 than to the antennae ; facets very gradually decreasing in size towards the 

 lower part. Antennae dull brownish black, but with the two basal joints 

 covered with dull whitish yellow dust ; basal joint bearing soft yellow hairs 

 about its base, but on the apical third mainly with strong stiff black bristles ; 

 second joint with rather dense short black bristles ; base of the third joint 

 and tip of the second narrowly brownish orange. 



Thorax dark brownish ashy grey, clothed with moderate (sometimes 

 obscure) dark yellow or greyish white fine pubescence of very equal length 

 but subordinated to abundant longer and more erect black hairs whose length 

 is also more regular than in the allied species ; chsetotactic bristles normal 

 but not very conspicuous, pr^scutellar bristles one pair only ; pleurae ashy 

 grey, with rather pale shaggy pubescence but with a few black hairs inter- 

 mixed under the wing-base and on the metapleurse ; metapleurse otherwise 

 with conspicuous long dense pale tawny pubescence amongst which a few 

 black hairs occur. Scutellum with pubescence similar to that on the thorax 

 but with a more yellowish tinge about the margin. 



Abdomen black, with conspicuous bright yellow hindmarginal hems to 

 the segments which vary but are usually broad on the second and very narrow 

 on the third and fourth segments, and Avith a greyish yellow (or when seen 

 sideways brownish) cross-band on each segment which is narrow at the middle 

 but widened so much against the sides that only a large rather indefinitely 

 triangular black spot remains, so that each black spot occupies at its base 

 the whole foremargin of the segment and then extends down (usually 

 rather abruptly) at the middle of the earlier segments to rather near the 

 hindmarginal hems, but on the subsequent segments the black band or spot 

 is more remote from the hindmargin, so that on the last segments very little 

 or nothing of the spot remains visible. Pubescence long and erect, dull 

 darkish yellow ventrally and laterally until almost on to the dorsal disc, but 

 on the dorsal disc itself very extensively and obviously mixed with black hairs ; 

 on the dorsal middle line (after the basal segment) a considerable number 

 of black hairs occur which can be seen most distinctly when viewed in a 

 very sloping direction from in front or behind, and there is a cross-band 

 of black hairs before the hindmargin of each segment which becomes broader 

 and less defined on each succeeding segment until black pubescence pre- 

 dominates all over the dorsal surface of the last segment. Belly yellowish 

 ashy grey, clothed with long erect yellowish pubescence ; second segment 

 with a narrow dull orange hindmarginal hem, and the third and fourth 

 segments with a broad hem ; base of the second, third, and fourth segments 

 inside the semicircular row of spiracles rather shining greyish black. 

 Genitalia mainly reddish orange with some orange pubescence, but the upper 

 lamellae more blackish. 



Legs black, with the tibiae luteous to reddish yellow or reddish brown 

 with just the tip blackish; tarsi with the basal joint (except its tip) and the 

 basal half or more of the second joint reddish brown ; front coxae clothed 

 with long greyish yellow pubescence and with four or five black bristles near 

 the tip which are hidden in the pubescence ; posterior coxae with darker grey 



fmbescence and less pronounced bristles. Pubescence on the anterior femora 

 ong and usually yellow about the base posteriorly, but blackish on the rest 

 of the front femora and on most of the middle pair ; hind femora almost 

 entirely covered with yellow scaly pubescence. Bristles on the anterior 

 femora limited to two or three inconspicuous antero-ventral, on the hind 

 femora to an irregular row of about ten antero-ventral with about four 

 others more ventral near the base and to three or four small neat postero- 

 ventral close to the tip ; front tibiae with three rows of four bristles ; posterior 

 tibiae with four rows of more numerous bristles except that the postero- 

 ventral row is composed of three strong and two weak bristles. 



