574 THEREVID^ 



all the black liairs on the fore part of the frons), the upper part of the frons is 

 the same colour as the fore part and is beset with sparse moderately short 

 black hairs amongst which single pale hairs are sometimes intermixed. 

 Face white, with rather dense and long all white pubescence without any 

 admixture of black hairs except that there is a slight continuation of the frontal 



black hairs at the sides to just below the antennae, 



and there are a few black hairs below the lowest part 



of the eyes though not nearly enough to call a clump ; 



back of the head whitish below and with whitish 



pubescence there which amalgamates with the similar 



white pubescence on and in front of the front coxas, 



but higher up as the ground colour becomes yellowish 



grey the pubescence becomes more yellow or orange ; 



there are six to ten black postocular bristles on the 



upper part and usually two or three more smaller 



Pig. z^z.—Thereva Upunctata ones nearer the middle of the back of the eye, besides 



? . X 16. the usual black bristles quite out on the back of the 



head. Antennae with the two basal joints light grey 



and the third joint greyish brown ; first joint with the usual black hairs 



and bristles on the apical half, but with whitish pubescence near the base 



at the sides and beneath. 



Thorax dull brownish, with two more or less indistinct grey stripes 

 and with a short depressed felt-like yellow pubescence intermixed amongst 

 which are almost equally numerous though inconspicuous almost upright 

 longer black hairs, but the ground colour hardly obscured j chaetotactic 

 bristles conspicuous as in fig. 311 ; pleura light ashy grey, with the pubescence 

 dense and shaggy yellow on the upper part and back of the mesopleur^, but 

 longer dense and whitish on the metapleurae, though occasionally a few black 

 hairs occur on the back part, while there are more sparse and whitish hairs 

 on the lower part of the pleurae. Scutellum with only a few of the erect 

 black hairs. 



Abdomen black, hardly shining, but the grey cross-bands occupying most 



of the disc, and the hindmarginal hems yellow ; these yellow hindmarginal 



hems are fairly conspicuous and rather narrow on the second segment, 



narrower or almost absent on the third segment, and hardly visible on the 



subsequent segments, or the hems may be distinct though narrow on all the 



segments from the second to the sixth, or again they may be fairly broad on 



the three basal segments and narrow but distinct on the next three ; basal 



segment usually all rather dark grey ;_ second segment with a broad pale ashy 



grey cross-band before the yellow hindmarginal hem which is narrowed at 



the middle to about one-third of the depth of the segment but widened out 



until it occupies fully two-thirds of the sidemargins ; third segment similar 



but the grey band slightly narrower; fourth segment with the grey band 



occupying nearly half the segment and more equal in width until close to the 



sides ; fifth segment usually all ashy grey except on a shallow black basal 



cross-band which scarcely extends to the sides ; sixth segment ashy grey 



with only a slight trace of a basal darkening ; seventh segment more shining 



black with the hindmargin and sides orange grey; eighth segment shining 



black ; ovipositor with the underside of the shining black eighth segment 



bright shining chestnut and with the usual circlet of dark red spines. 



Pubescence black and recumbent on the black parts of the disc but yellow on 



all the rest, and forming a fringe over (not on) the yellow hindmarginal hems ; 



some moderately long and abundant whitish yellow hairs occur on the sides 



of the basal segment and on the front corners of the second segment ; on the 



fourth segment a few erect hairs occur on the sides, and all the hairs on the 



next three segments are erect and conspicuously yellow, especially on the 



seventh seqment. Belly pale grey, with sometimes an almost whitish sheen on 



the four basal segments ; the yellow hindmarginal hems conspicuous on the 



second, third, and fourth segments and just visible on the fifth and sixth ; 



pubescence yellowish, forming a depressed fringe near the hindmargin of 



the fourth segment and on the hindmargins of the fifth, sixth, and seventh 



segments, but the other pubescence on these last three segments erect and 



almost orange. 



