DURHAM DIPTERA. 325 



XLL 

 Family XLI.— ORTALID^E. 



TABLE OF GENERA. 



1 (4). Antennae very long and horizontal, profile triangular, 



face retreating almost horizontally (VII. 1, 2). 



2 (3). Fronto-orbital bristles present (VII. 2); hind tibiae 



with a praeapical bristle. 

 516. Trigonometopus, Mcq. (H~etero?ietirid<z) 



(2288. frontalis, M g. ) 



3 (2). Fronto-orbital bristles absent (VII. 1); hind tibiae 



without praeapical bristle. 



537. Dorycera, Mg. (2375. graminum, F.) 



4 (1). Antennae not long, or, if long, then drooping; profile 



perpendicular, or only slightly retreating (VII. 3, 4). 



5 (6). Back of the head hollowed out above and inflated 



below ; upper mouth-edge considerably produced 



(VII. 3)- 



545. Platystoma, Mg. (2394. seminationes, F.) 



6 (5). Back of the head somewhat inflated both above and 



below; upper mouth-edge not produced (VII. 4). 



7 (18). V.4. not, or only very slightly bent towards V.3. 



8 (15). Third antennal joint shortly elliptical or oval, at most 



twice as long as the second. 



9 (12). Front of the third antennal joint with a sharp upper 



corner, concave above. 



10 (11). Praesutural bristles present. Ceroxys, Mcq. (543) 



11 (10). Praesutural bristles absent, only alar and praescutellar 



bristles present. Anacampta, Lw. (544) 



12 (9). Front of the third antennal joint rounded or blunt. 



13 (14). Head, and especially the frons, inflated. 



538. Tetanops, Fin. (2376. myopina, Fin.) 



14 (13). Head and frons not inflated. 



14a (14b). Wings light brown with round clear spots; V.4*bent; 



dorsum bristly to the front. Ptilonota, Lw. (539) 

 14b (14a). Wings clear with dark brown bands; V.4 4 straight; 



dorsum bristly only behind and at the sides. 



Ortalis, Fin. (540) 



15 (8). Third antennal joint linear, always at least three 



times as long as the second. 



