DUKHAM DIPTEBA. 1 73 



XXVIII. 271. 



5 (2). Pubescence on the hind tibiae of the male all black. 



Abdomen of female with a pair of round reddish 

 spots. (143°. flavitarsis, Mg.) 



6 (1). Upper outer corner of 0.4 2 very distinctly acute. 



(143 1. heringi, Ztt.) 



272. Pipiza, Fin. 

 The distinction of many of the species is very uncertain. 



1 (2). Fore and mid tarsi all yellow ; pubescence all yellow 



on both thorax and abdomen. 



(1432. luteitarsis, Ztt.) 



2 (1). Fore and mid tarsi blackened, at least at the tip; 



pubescence not all yellow. 



3 (4). Abdomen normally with four yellow spots. 



(1433. quadrimaculata, Pz.) 



4 (3). Abdomen normally with two pale spots, or streaked, 



or unspotted. 



5 (8). Legs very yellow about the knees and the base 



of tarsi (moderately shining, coarsely punctate 

 species). 



6 (7). Size 6^—9 mm. 



1434. Pipiza noctiluca, L. 

 Belburn, 1 $, June, 1898; Bishop Auckland, 3 ?, 

 June-July, 1901 ; " Killingworth," C. Robson. 



7 (6). Size 10 mm. Pale abdominal spots, in the female 



very conspicuous. ( I 435- fenestrata, Mg.) 



8 (5). Legs not very yellow about the knees and tarsi. 



9 (12). Shining black species, moderately punctate. 



10 (11). Size about 8 mm. (1436. bimaculata, Mg.) 



11 (10). Size about 6 mm., and more oblong. 



(i437- signata, Mg.) 



12 (9). Duller species, coarsely punctate. 



13 (14). Very small, 5 mm. Abdomen distinctly spotted. 



(1438. notata, Mg.) 



14 (13). Larger, about 9 mm. Wings strongly clouded. 



(1439. lugubris, F.) 



