20 PROF. M. BEZZI. 



black on the back, with short yellowish pubescence and with dark grey dust, which 

 makes it opaque ; the pleurae are more shining, but always with a faint grey 

 dust. The bristles are black and strong ; dc. placed before the line of the a. set. ; 

 1 mpl. ; st. much stronger than the pt. ; scp. not distinct. Mesophragma shining: 

 black ; scutellum short and broad, very like the thorax, with only the basal pair 

 of bristles, which are strong and very long. Halteres pale yellowish. Abdomen 

 long and narrow, entirely black, with a dark brassy dust, with short black pubescence- 

 and with undeveloped bristles at end ; it is slightly but distinctly shining ; ovipositor 

 more shining ; venter entirely black. Legs rather long ; coxae dark brown, with 

 whitish dust ; femora black, with narrowly reddish tips ; 4 anterior tibiae reddish, 

 more broadly on the front pair ; tarsi reddish ; front femora with 2 stout bristles, 

 beneath ; hind tibiae without posterior row of bristles. Wings like those of angusta, 

 but not so narrow at base, the axillary cell being well developed ; costal bristle long; 

 and double ; stigma short ; 3rd longitudinal vein at end parallel with the 4th ; 

 small cross-vein placed on the last fifth of the discoidal cell ; hind cross-vein much, 

 longer than its distance from the small one, and S-shaped ; lower angle of the anal 

 cell acute but not produced. The pattern is very like that of angusta ; but there 

 is no isolated black band in the hyaline part of the base, there being only a marginal 

 streak in the 1st costal cell, ending obliquely in the middle of the 2nd costal cell ; 

 of the two hyaline indentations of the fore border, the first ends truncately at the 

 3rd and the 2nd ends acutely at the 4th vein, the black streak between them being 

 oblique and rather broad. The three indentations of the hind border are oblique 

 and narrow ; the first crosses the base of the discoidal cell, ending at the 4th vein ; 

 the 2nd, which is the narrowest and shortest of all, enters with a point into the 

 discoidal cell ; the 3rd ends at the fourth vein just along the hind cross- vein. There 

 are no hyaline isolate spots ; the axillary cell is greyish hyaline. The veins are 

 black, but they are pale yellowish in the hyaline indentations, which are distinctly 

 whitish in colour. 



Type $, a single specimen from N. W. Rhodesia, Chilanga, 30.vii.1913- 

 (R. C. Wood). 



4. Aciura caeca, Bezzi, Bull. Soc. Ent. Ital., xxxix (1907), 1908, p. 150. 

 Distinguished by the entirely black discoidal cell and by^the second costal cell, 



not being margined with fuscous. 



Originally described from Erythraea, Keren, and not found subsequently. 



5. Aciura tetrachaeta, sp. nov. (PI. i, fig. 4). 



Very like the above-described semiangusta, but distinguished by its greater size,. 

 4 scutellar bristles and differently patterned wings. 



$. Length of the body, 5 mm. ; of the ovipositor, 3 mm. ; of the wing, 5 '5 mm. 

 Head and its bristles and appendages as in semiangusta, but the front is more lightly 

 coloured and has no distinct black, triangular ocellar plate ; the lunula is much . 

 broader and more developed than usual. Thorax, scutellum and mesophragma 

 entirely brassy black, rather shining, with faint dust ; on the back the short pubes- 

 cence seems to be black ; the bristles are black ; the apical pair of the scutellum . 

 are half as long as the basal ones and cross each other. Halteres with black knob. . 



