DURHAM DIPTERA. 73 



XII. 109. 



7 (6). Male genitalia with two very long sickle-shaped black 



processes. 



716. Molophilus bifilatus, Verr. 



Hesleden, 1 $, August, 1900. 



8 (1) (11). Dark grey species. 



9 (10). Knob of the halteres whitish. 



717. Molophilus obscurtis, Mg. 

 South Durham, 1 $ ; Hesleden, 1 ?, 3-8-02. 



10 (9). Knob of the halteres blackish. (718. murinus,M.g.) 



11 (1) (8). Deep black species. (7 10 - a ter, Mg.) 



110. Rhypholophus, Kolen. 



Life history unknown. 



1 (6). V.7. straight and rather short. Antennal joints 



petiolate (stalked) in the male. 



2 (5). Brownish grey species. 



3 (4). Thorax with a centre stripe. 



720. Rhypholophus lineatus, Mg. 

 Stanhope, 2 $, 23-5-00. 



4 (3). Thorax not striped. 



721. Rhypholophus nodulosus, Mcq. 

 Common everywhere. 



5 (2). Yellow species. 



723. Rhypholophus similis, Staeg. 

 Deepdale, Yorks, 1 % 26-6-01. 



6 (1). V.7. twisted and long. Antennal joints not stalked, 



close together. 



7 (8). Thorax with four distinct stripes. Wings consider- 



ably mottled. 



724. Rhypholophus varius, Mg. 

 Wearhead, 2 $, 20-8-01. 



8 (7). Thorax indistinctly striped. Wings less mottled. 



725. Rhypholophus hcemorr holdalls, Ztt. 

 Wearhead, 1 $, 20-8-01. 



