DURHAM DIPTERA. 1 55 



XXIV. 242. 



12 (13). Face all golden green, with the exception of the grey 



cross-band. Large species, 3-4 mm. 



(1322. diadema, L.) 



13 (12). Face wholly dusted, or at least on the upper half. 



Small species. 



14 (15). Acrostichal bristles very short. (1323. flavipes, Mg.) 



15 (14). Acrostichal bristles fairly large and distinct. i£mm. 



(132 1. pallipes, Ztt.) 



16 (7). Legs black with yellow knees. 



17 (18). Face all dusted whitish grey. (1324. jaculus, Mg.) 



18 (17). Face metallic, at least on the lower part. 



19 (20). Acrostichal bristles fairly large and distinct. Lower 



part of the face green. (1320. apicalis, Ztt.) 



20 (19). Acrostichal bristles very short. Lower part of the 



face blue-green. 



21 (22). V.5 4 longer than X.5. Small species, 2 mm. 



(1325. truncorum, Mg.) 



22 (21). V.5 4 at least not longer than X.5. 



23 (24). V.4 1 and V.4 2 about equal. Small species. 



(1326. dendrobcenus, Kow.) 



24 (23). V.4 1 distinctly longer than V.4 2 . Largish species 



with handsomely striped thorax. 



(1327. petrophilus, Kow.) 



243. Scellus, Lw. 



1328. Scellus notatus, F. 

 Bishop Auckland, 1 $, June, 1900; Hesleden, 4 $> , 

 August, 1900-01. 



244. Hydrophorus, Whlbg. 



1 (2) (6). Wings with many brown points, especially near the 



fore margin. 

 1329. Hydrophorus nebulosus, Fin. 

 Waskerley, 3 $, 23-5-03. 



2 (1) (6). Wings with only two rather faint dark spots on 



V.4 3 and X.5. 



