326 DURHAM DIPTERA. 



XLL 



16 (17). Face keeled, i.e., with a central ridge from the antennae 



to the mouth. Pterop^ectria, Lw. (541) 



17 (16). Face not keeled. 



546. Rivellia, Dsv. (2395. syngenesis, F.) 



18 (7). V.4. distinctly bent towards V.3. 



19 (20). Antennae approximate at the base ; frons moderately 



broad, dull, and without indentations. 



547. Seoptera, Kirby (2396. vibrans, L.) 



20 (19). Antennae distant at the base ; frons unusually broad, 



shining, and with indented marks and points. 



21 (22). Antennae in a pit ; 0.6. short. Ulidia, Mg. (548) 



22 (21). Antennae free; 0.6. almost reaching the margin. 



549. Chrysomyza, Fin. (2398. demandata, F.) 



tables op species. 

 539. Ptilonota, Lw. 



1 (2). V.4 4 looped ; wings pale brown with 5-6 clear spots. 



(2377. guttata, Mg.) 



2 (1). V.4 4 simply bent ; wings with the clear places larger, 



almost as if banded. (2378. centralis, F.) 



540. Ortalis, Fin. 



1 (2). Legs black. (2379. gangrenosa, F.) 



2 (1). Legs orange. (2380. ortiata, Mg.) 



541. PteropjECTria, Lw. 



1 (4). Face entirely shining black. 



2 (3). Frons shining black. (2384. paludum, Fin.) 



3 (2). Frons bright orange. (2385. palustris, Mg.) 



4 (1). Face wholly or mostly orange. 



5 (6). Wings mostly dark brown with clear bands, one com- 



plete from fore to hind margin between X.4. and 

 X.5 2 , one before X.4. from fore margin to V.6., 

 one beyond X.5 2 from hind margin but not reach- 

 ing V.3. ; tip, and basal hind margin also clear. 

 2386. Pteropcectria frondescentice, L. 

 Waskerley, 1 $, July, 1901 ; Hesleden, 5 $ and 4 ?, 

 August, 1902. 



