19U5.] 109 



1 (14) .Middle coxtB with a strong black apical spine. 



N.B.^This spine frequently splits up into two or three closely appro.ximated bristles. 



2 (3) Arista with a leaf-like dilation at tip ; hind femora with one preapical spine... 



1. antennata Carl. 



3 (2) Arista practically normal. 



4 (7) Face black ; beard black or blackish ; hind femora without any preapical spine. 



5 (6) Outer genital liiiuellae (orkcd ; hind tibias yellow, becoming black towards tip ; 



basal joint of front tarsi thin, as long as the other four together, and with a few 

 longer thin hairs at tip beneath 2. spinicoxa Lw 



6 (5) Outer genital lanielliB not forked ; beard brown ; hind tibire conspicuously 



whitish from near base to middle, and with apical half dilated, channelled, and 

 blackish ; basal joint of front tarsi thin, barely as long as next three together ; 

 squamas dark fringed 3. fascipes M eig. 



7 (4) Face and beard white ; hind femora with one or more preapical spines. 



8 (9) Last abdominal segment (the one before the hjpopygiuni) purplish ; 



thorax brilliant green ; hind femora with two or more jjreapical spines ; basal 

 joint of front tarsi barely as long as next two together ; outer genital lamellae 

 long, not forked, hairy ; front femora almost bare ; large species... 



4. eleffautula Aleig. 



9 (8) Last abdominal segment concolorous with the others ; hind femora with one 



preapical spine. 



10 (1 1) Third joint of antennas longer than arista ; thorax rather dull greenish ; basal 



joint of front tarsi not clubbed and not much longer than second ; outer lamellse 

 long, but not exceedingly long, and not bifid ; small species... 



5. iiemorum Meig. 



11 (10) Third joint of antenna shorter than arista. 



12 (13) Last joint of front tarsi with 4-5 remarkable long hairs ; basal joint of front 



tarsi hardly longer than second joint and not dilated at its tip ; thorax dullish 

 green 6. rivalis Lw. 



13 (12) Last joint of front tarsi with no long hairs ; lamellse exceedingly long; basal 



joint of front tarsi twice as long as second and clubbed at its tip ; thorax dull 

 blackish-green with two black stripes ; arista faintly dilated just before its tip... 



7. patula Radd. 



14 (1) Middle coxae without a strong black apical spine, though a tuft of black 



bristly hairs may occur there. 



15 (16) Last two joints of middle tarsi dilated ; narrow face and beard white ; an- 



terior femora and all coxse with whitish pubescence ; posterior coxse with 

 distinct tufts of black bristly hairs ; hind femora without any preapical spine ; 

 hind tibiae stout and black ; basal joint of front tarsi longer than rest together 

 and clubbed at its tip ; outer lamellie very long, thin and forked... 



8. crassipes Meig. 



16 (15) Last joints of middle tarsi normal. 



17 (20) Front femora with a black pectination beneath ; outer lamelte short and 



broad, not forked. 



18 (19) Face and beard black ; front femora with a strong black pectination beneath on 



the basal third consisting of about nine spines, then quite bare for a considerable 

 space, followed on the aisical third (or more) with thin black oiliation ; hind 

 femora with one small prcai)ieal spine ; basal joint of front tarsi longer than 

 next three together, though the two basal joints are elongate and twisted... 



9. pectinata Lw. 



19 (18) Face and beai'd white ; front femora with a continuous black pectination beneath 



