18 PROF. M. BEZZI. 



XXII. Acitjra, Robineau-Desvoidy (1830). 



The condition of this and the two following genera is at present quite unsatis- 

 factory, as they include evidently different elements. Even the two typical European 

 species of Aciura are hardly to be considered as congeneric ; rotundiventris has 

 black vt. bristles, occiput swollen above, eyes narrow in profile, yellow pubescence 

 on thorax, short and broad ovipositor and no, or ill-developed, costal bristle on the 

 wings ; while coryli has yellowish vt. bristles, occiput hollowed above, eyes more 

 rounded, black thoracic pubescence, long and narrow ovipositor and a well developed 

 costal bristle, which is often double. 



I have now distinguished the genera only on account of the dusted or not dusted 

 back of mesothorax, without considering the colour of the bristles of the occipital 

 row or the number of the scutellar bristles. Thus! have included in Aciura species 

 with all these characters ; in Platensina the bristles of the occipital row are usually 

 of the stout and obtuse type, but as they are sometimes thin, I have in the table 

 of the genera repeated the genus. 



The Ethiopian species provisionally placed in Aciura can be distinguished as 

 follows : — ■ 



1(14). All the bristles of the occipital border are whitish, only the longer inner 

 vt. being black ; wings black at hind border, with 3 or 4 hyaline indenta- 

 tions ; body elongate. 



2(3). Wings quite cuneiform, with a very narrow base and with rudimentary 

 axillary cell ; only 2 scutellar bristles ; thorax on the back with black 

 pubescence . . . . . . . . . . . . angusta, Loew. 



3(2). Wings not cuneiform, with normally developed axillary cell ; scutellum 

 usually with 4 bristles 



4(13). No hyaline spots on the middle of the wings, or only a single dot or streak 

 in the black apical patch ; the hyaline indentations of the hind border 

 are long and narrow, not paired. 



5(12). Wings with only 3 hyaline indentations at the hind border, the apical one 

 in the first posterior cell being wanting. 



6(7). There is a hyaline spot in the middle of the apical black patch 



oborinia, Walk. 



7(6). No hyaline spot in the apical black patch. 



8(9). Only 2 scutellar bristles ; axillary cell rather narrow ; the 2 hyaline indenta- 

 tions of the 3rd posterior cell extend with their tips into the discoidal 

 cell ; thorax with yellow pubescence ; halteres pale yellowish 



semiangusta, sp. n. 



9(8). Scutellum with 4 bristles ; axillary cell rather broad ; the first two indenta- 

 tions of the hind border stop at the 5th longitudinal vein, the discoidal cell 

 being entirely black ; thorax with black pubescence ; halteres black. 

 10(11). In the hyaline base of the wings there is only a short black border in the 

 first costal cell . . . . . . . . . . . . caeca, Bezzi. 



11(10). There is a broad black marginal stripe in the two costal cells extending from 

 the base to the stigma . . . . . . . . . . tetrachaeta, sp. n. 



