1. THEREVA 563 



noMlitata, in fact so much so that at one time I mistook it for T. hipundata 

 from which however the wing coloration clearly distinguishes it ; Meigen 

 said that he bred this species from larvfe found in old rotten tree-trunks. 



Synonymy. — All Fabricius' descriptions of this species are unrecognisable, and 

 consequently it should really date from Meigen's first description in 1804. Speci- 

 mens in which the pubescence on the abdomen tends towards reddish yellow and in 

 which at the same time the black pubescence is especially extensive would fairly 

 answer to Meigen's description of T. cincta. Walker's description of his T. plebeia 

 is most likely derived from the female of T. nobilitata, but these two species were 

 hopelessly mixed in old British collections. Walker's T. cincta Meig. is also most 

 probably only T. nobilitata, but with the description mainly derived from the male. 



4. T. plebeia Linne. Thorax blackish and mainly black haired in the 

 male. Abdomen of the male extensively black and with black dorsal and 

 pale ventral pubescence, of the female mainly black with whitish grey 

 bands and with rigid black pubescence on the last four segments. 

 Frontal callus of the female very large. 



A rather broad species of mainly blackish hue, but with 

 conspicuous ashy grey bands on the abdomen of the female. 



S . The following description is made from a representative male taken on the 

 Malvern Hills on May 14, 1899. Face and frons ashy grey, but the frons 

 rather greyish yellow about the middle, and the face shimmering whitish 

 about the sides on especially the lower part, and this shimmering whitish 

 hue extends under the eyes and on to the lower part of the back of the 

 head ; pubescence on the frons long dense and wholly black (except close 

 against and around the base of the antennae), and similar pubescence extends 

 more sparsely down the sides of the face but is reduced to almost a single line 

 of hairs or even practically dies out on the lower quarter, but there is a small 

 clump of black hairs beneath the lower eye-angle ; face clothed on the middle 

 part with long whitish or yellowish grey pubescence with some black hairs 

 intermingled ; pubescence on the lower quarter of the back of the head 

 mainly pale greyish yellow but with longer black hairs behind, and brownish 

 yellow on the back part of the upper three-quarters, while there is a 

 single postocular fringe of about thirty-five long thin black hairs on about 

 the upper half overhanging the eyes and extending up to their top corner, 

 though the lower part of this fringe is shorter and comparatively sparse ; 

 vertex brownish grey, elevated, and bearing numerous black hairs which are 

 less dense and shorter than those on the frons. Eyes touching for a fairly 

 long space, but leaving the vertical longer than the frontal triangle ; facets 

 gradually diminishing in size towards the lower part. Antennae dull greyish 

 black, but yellowish grey on the basal joint ; basal joint bearing fine pale 

 pubescence about its base but this pubescence (especially dorsally) soon 

 becoming black, and the apical third of the joint bearing the usual longer 

 stiff black bristles ; style short. 



Thorax and scutellum greyish black (in comparison with the brownish 

 hue of T. n/)bHitata) and with two very faint pale stripes down the disc ; 

 pubescence dense but mixed, being composed of conspicuous long erect black 

 hairs and less conspicuous more decumbent shorter brownish yellow hairs, 

 though when viewed from in front in certain lights the brownish yellow (not 

 ferruginous or tawny) pubescence appears to almost cover the front part of 

 the disc and to be abundant about the sides, on the back part, and on the 

 scutellum, while numerous but less abundant similar hairs occur on the disc ; 

 chajtotactic bristles normal, and the prsescutellar bristles limited to one pair. 

 Pleurae more ashy grey, and clothed with tangled long light brownish yellow 

 pubescence, but the dense tufts on the back part of the mesopleurae and on 

 the metapleurje largely composed of long black hairs except on the upper part 

 of the mesopleural tuft. 



