364 DURHAM DIPTEEA. 



LI. 637. 



5 (4). Costa ending at the end of V.3. ; palpi large. 



{rmgens, Lw.) 



6 (3). Wings clear-translucent or clear-grey. 



7 (8). Third antennal joint with unusually long pubescence. 



{dasycera, Lw.) 



8 (7). Third antennal joint with the usual quite short 



pubescence. 



9 (10). Fore tarsal joints very much shortened in the male ; 



all fifth tarsal joints large, especially in the male. 



(2704. brevimana, Lw.) 



10 (9). Fore tarsal joints of the male not shortened. 



11 (28). Third antennal joint always quite black. 



12 (23). Sternopleural and hypopleural spots both entirely 



black. 



13 (16). Fore metatarsus black. 



14 (15). Second and third tarsal joints entirely pale, or at 



least at their bases or under sides ; vertical triangle 

 with a broad flat central channel. 



tceniopus, Mg. (2705) 



15(14). Fore tarsi entirely black ; vertical triangle without a 



channel or impressed middle line, {brevifrons, Lw.) 



16 (13). Fore metatarsus yellow, or at least brown. 



17 (20). Large species, 2^-4 mm. 



18 (19). Third antennal joint small. speciosa, Mg. (2707) 



19 (18). Third antennal joint large. (planifrons, Lw.) 



20 (17). Small species, 1^-1^ mm. 



21 (22). The vertical triangle with yellow corners. 



{minuta, Lw.) 



22 (21). The vertical triangle entirely black. {humilis, Lw.) 



23 (12). The entire sternopleural spot pale, or only black on its 



upper edge. 



24 (25). Palpi much larger than usual. {rmgens, Lw.) 



25 (24). Palpi of the usual size. 



26 (27). The second antennal joint with no black dot on its 



upper side. {serena, Lw.) 



27 (26). Second antennal joint with a prominent black dot at 



the base of its upper side. {puncticornis, Lw.) 



