1. THEREVA 551 



until tlie middle of the base of the fourth and fifth segments, wliere about 

 three or four almost microscopical rather erect black hairs exist, but on the 

 sixth segment all the pubescence is erect and rigid and the tiny erect black 

 hairs may predominate ; seventh segment shining black, but slightly dusted 

 with yellow at the sides towards beneath, and with its pubescence sometimes 

 all yellow but sometimes black except on the yellow dusted part ; eighth seg- 

 ment shining black and bearing short rigid black hairs. Belly with thin but 

 nearly erect and almost all yellow pubescence which is shorter than in the 

 male, though a few black hairs may occur down the middle of the fifth 

 and sixth segments and sometimes all over the seventh segment ; eighth 

 segment forming a bare ventral genital plate. Ovipositor with numerous 

 short thick-set dark tawny spines, but with the usual circlet not so well 

 defined as usual. 



Legs with the coxae light ashy grey (like the pleurse just above_ them) and 

 bearing whitish grey pubescence; pubescence behind the anterior _ femora 

 very much shorter, less conspicuous, and all yellow ; hind tibiie with four 

 rows of bristles, but the antero-ventral row consisting of only four bristles. 



Wings without any trace of darkening at the upper outer corner of the 

 discal cell. Squamse more whitish glassy, with a brownish yellow margin 

 and pale fringe. 



Length about 9-5 mm. 



'O"- 



This species varies a little in the amount of black hairs intermixed 

 with the tawny pubescence on the thorax, on the sides of the face, and 

 on the dorsal line of the abdomen. A remarkable male taken by 

 Colonel Yerbury at Porthcawl on June 10, 1903, has the frons moderately 

 wide but bare between the eyes, and with an indication of black calli 

 where it widens out, the face with but few black hairs, the postocular 

 ciliation more confined to the upper part and composed of about twelve 

 bristles, the pubescence on the thorax short and depressed, the abdomen 

 with scarcely any black dorsal hairs, the seventh and eighth segments 

 more blackish, and the genitalia smaller ; I do not think it is a herma- 

 phrodite, but I consider it to be a male with numerous female cbaracters. 

 This species may be distinguished from all British allies by its almost 

 entirely bright fulvous pubescence, and also from most of them by its 

 two pairs of praescutellar bristles; occasionally other species have two 

 pairs of these bristles, and its nearest continental ally, T. suhfasciata, 

 appears to always have them, but the male of T. suhfasciata has paler 

 pubescence and has an inconspicuous fine hindmarginal fringe of black 

 hairs right across the abdominal segments, whereas the male of T. fulva 

 has the dorsal black hairs (even when they exist) not confined to the 

 hindmargin and not spread far away from the dorsal line. The female 

 of T. siibfasciata may be easily distinguished by its dulled lighter colored 

 seventh abdominal segment. T. suhfasciata is almost certain to occur in 

 Britain, as it is not uncommon in North Germany and Scandinavia. 



T. fulva is decidedly uncommon in Britain and although all our old 

 lists included it I have failed to find it in any old collections, the 

 specimens representing it being nearly always T. nohilitata. It is how- 

 ever a very distinct and very beautiful species, but requires great care 

 in collecting to preserve its brilliant pubescence intact. I first caught 

 it near Farningham Eoad Station in Kent on June 18, 1868, when I 

 believe it was not uncommon, and I took anotber male at Foot's Cray 

 in the same neighborhood, while Colonel Yerbury found it not uncommon 

 at Dartford in July 1908, which makes it probable that Stephens (who 

 often collected in Kent) may have correctly identified the species. Colonel 



