Lydella. 295 



62. Lydella R. D. 



Medium sized species of black colour, more or less greyish prui- 

 nose, the male sometimes with reddish abdominal side spots. The 

 genus stands near Ceromasia. Head as broad or fully as broad as 

 thorax, more or less convex behind and puffed out below. Frons 

 in male narrower or broader, in female broader than in male; it is 

 distinctly protruding. Jowls narrow to half as broad as the height of 

 the eye. In both sexes ocellar and inner vertical bristles, in female 

 further outer vertical and two orbitals; in male generally also weak 

 outer vertical bristles. Distinct postocellar and occipital bristles. 

 Behind postocular bristles black hairs, in one row or mainly so. Frontal 

 bristles descending at most to insertion of arista, two uppermost 

 reclinate in both sexes; (in angelicae female the upper frontal bristle is 

 transverse). Cheeks bare. Vibrissæ slightly or a little more ascending, 

 but not reaching middle. Eyes bare. Epistoma somewhat retreating, 

 slightly or almost not reflected below. Antennæ inserted above 

 middle of the eye, or {angelicae) at the middle; third joint from one 

 and a half to three times as long as second; arista with second joint 

 short to slightly elongated. Palpi thin or more or less dilated out- 

 wards. Thorax rectangular; three or four postsutural dorsocentrals, 

 and two or three præ- and three postsutural acrostichals; a præ- 

 sutural intraalar bristle present, sometimes wanting {angelicae). 

 Scutellum with three or four marginal bristles on each side, the 

 apical pair wanting or only small hairs, or they are longer, crossing 

 and somewhat erect. Three or four sternopleural bristles. Abdomen 

 elongated conical; excavation on second segment reaching hind 

 margin, except in angelicae; there are discai and marginal bristles, 

 second segment with a pair of marginal. In some species the male 

 has on ventral side of fourtli segment a patch of short dense hairs on 

 each side; in one species {nigripes) the female has the ventral lateral 

 margins of the segments raised and pressed together, and this keel 

 is on third and fourth segment beset with short, strong spines so that 

 a saw is formed along the middle of venter. Legs strongly bristled; 

 anterodorsal bristles on hind tibiæ unequal; claws and pulvilli in 

 male elongated; front tarsi in female simple. Wings with the bristles 

 at base of cubital vein in one species {angelicae) produced towards 

 medial cross-vein; no or a small costal spine, in angelicae strong. 



The genus mainly differs from Ceromasia by the elongated claws 

 and pulvilli in male, and by the in this sex wanting or weak outer 

 vertical bristles. 



