DUEHAM DIPTERA. 51 



VI. 72. 



47 (48). Dark dusky olive and black species. 



(420. chloris, Mg.) 



48 (47). Species with pale or green abdomen. 



49 (52). Abdomen pale with dark end. 



50 (51). Halteres all pale. 



422. Chironomus pedellus, Deg. 

 Bishop Auckland, 2 $. 



51 (50). Halteres with black knobs. (423. pedestris, Mg.) 



52 (49). Abdomen bright green. 



53 (54). Thoracic stripes dark fuscous. (433- pusillus, L.) 



54 (53). Thoracic stripes shining black. 



(434. prasinatus, Staeg.) 



55 (46). Thorax green with pale stripes. (429. paganus, Mg.) 

 66 (35). Fore metatarsus white. 



57 (58). Tarsi with two white rings. Thorax entirely green. 



(431. bianmilattis, Staeg.) 



58 (57). Fore tarsi with one ring. 



59 (60). Thorax green with red stripes. (432. virescens, Mg.) 



60 (59). Thorax all shining black. (437« albimanus, Mg.) 



73. Cricotopus, v.d. Wulp. 



1 (4). The white rings on the tibiae only, the tarsi all black. 



2 (3). Thorax all black. (460. tibialis, Mg.) 



3 (2). Thorax yellow in front. (463. ephippium, Ztt.) 



4 (1). Tarsi partly pale. 



5 (8). Fore tarsi with hairs in the male. 



6 (7). Thorax shining Hack, fore tibiae and tarsi all black. 



(obscurimamis, Ztt.) 



7 (6). Thorax yellow with black stripes, all tibiae and tarsi 



white-ringed, except the fore tarsi. 



(462. pilitarsis, Ztt.) 



8 (5). Fore tarsi bare in the male. 



9 (16). Mid and hind femora nearly all black. 



10 (11). Abdomen with two broad black bands on the third 

 and fourth rings. 



464. Cricotoptis bicinctus, Mg. 

 Very common at Bishop Auckland in spring. 



