74 [April, 



15. — H. lEKlTANs, Fin. Male : Eyes ivith a few short, scattered hairs, con- 

 tiguous ; arista distinctly imhescent for almost its whole length. Thorax hlackish 

 or blackish-olivaceous, slightly shining, when seen from behind covered with 

 yelloivish- cinereous tomentum, which leaves three hroad black indistinct stripes; 

 shoulders yellowish-cinereous ; inner dorso-central {= " acrostichal ") bristles 

 almost as long and conspicuous as the outer. Abdomen olive-brown, covered with 

 dense yellowish-cinereous tomentum, which leaves a smooth longitudinal central 

 stripe of the brownish ground-colour. Front femora with two teeth, the anterior 

 one large and blunt, the posterior one small and inconspicuous, a row of four to six 

 very long postero-ventral bristles in basal half (among which are a few shorter 

 ones) and a complete row of short and fine, erect, widely spaced ventral bristles ; 

 front tibise distinctly curved, with two deep ventral excavations in basal third, and 

 a shallow one about the middle, so that there appear to be two triangular projec- 

 tions, which are much more conspicuous than in any other species, also with two 

 long fine subapical postero-ventral bristles ; 1st Joint of tarsus with a regular fringe 

 of anterior and posterior stiff pubescence, amongst which are a few long fine hairs. 

 Middle tibise when seen from the dorsal aspect very slightly hollowed beyond 

 middle of anterior surface, basal two-thirds of same surface with a fringe of 

 moderately long stiff pubescence ; 1*;^ Joint of middle tarsus with a dense ventral 

 cushion of stiff slightly curved bristles. Hind femora long, suhclavate and slightly 

 curved; hind tibix slightly bent in middle, with, a fine dorsal bristle at one-third 

 from apex, antero-dorsal surface regularly fringed with stiff hairs, one to two fine 

 postero-ventral bristles at one-third from apex, antero- ventral surface with three 

 regularly disposed, erect, conspicuous bristles near apex, and finally a thick cushion 

 of stiff hairs occupying apex of ventral and postero-ventral surfaces. Wings 

 hyaline or tinged with yellowish-brown, usually strongly tinged with yellow at base, 

 last section of fourth longitudinal vein about twice as long as the penultimate ; 

 calyptra strongly tinged with yellowish-brown ; halteres yellowish-brown. Size, 

 5^—6^ mm. 



Female : Frons blackish and thickly covered with yellowish-cinereous tomen- 

 tum ; orbits and ocellar triangle light yellowish-cinereous ; silvery spot at base of 

 antennae large and conspicuous ; arista distinctly pubescent. Thorax thickly 

 covered with yellowish-grey tomentum, four rather indistinct longitudinal stripes 

 of olivaceous ground-colour, the two middle ones sometimes coalescing to form 

 a band, inner dorso-central bristles large and conspicuous, usually only a single pre- 

 sutural pair. Abdomen unformly oilve-cinereous , no trace of dorsal stripe or other 

 markings. Front tibiae with only a single subapical doi'sal bristle; middle tibise 

 with two posterior bristles at one-fourth and one-half from apex respectively. 

 Hind tibise with one subapical dorsal, one median antero-dorsal, one median postero- 

 dorsal, and one antero-ventral bristle at one-third from apex. Wings hyaline, 

 slightly tinged with yellow at base ; calyptra tinged with yellowish-brown, but not 

 60 strongly as in $ ; halteres light yellowish-brown. 



This species is to be found almost everywhere, being one of the 

 commonest of British Diptera. The females are most troublesome 

 and persistent, following one in clouds and well deserving of their 



