114 THE CANADIAN" ENTOMOLOGIST. 



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5. Mid tibia with the apical spur strong and distinctly bent; male 



hypopygium large, knob-like, curved back beneath abdo- 

 men Cetema Hendel. 



Mid tibial spur short and straight; male hypopygium not 

 conspicuous '. 6 



6. Scutellum flattened on disk, with a distinct marginal rim, the 



apical scutellar bristles *closely approximated; both sexes 

 with an elongated oval, flattened surface (sensory organ) on 

 hind tibia (postero-dorsal surface) Chloropisca Loew. 



Scutellum convex, not margined, apical bristles not approxi- 

 mated 7 



7. Sensory organ present on hind tibia, as in 



Chloropisca Pseudochlorops, n. gen. 



Sensory organ absent from hind tibia 8 



8. Head very distinctly produced in front; ocellar triangle very 



broad at vertex, carried forward to above antenna 1 in a 

 broad prolongation, the centre convex, the sides of frons 

 more or less excavated; third joint of antennae distinctly 

 longer than broad; arista generally appearing flattened 

 through the presence of thick 



pubescence Ectecephala Macquart. 



Head only slightly, or not at all, produced in front; frontal 

 triangle triangular, or subtriangular, flat; sides of frons 

 more or less excavated 9 



9. Cross-veins strongly approximated ; veins 2 and 3 bent for- 



ward Diplotoxa Loew. 



Cross-veins not approximated; veins 2 and 3 almost 



straight 10 



10. Third antennal joint disc-like; head not produced anteriorly; 



mesonotum yellow, with black or red stripes, seldom black, 

 and indistinctly punctured or 



unpunctured Chlorops Meigen. 



Third antennal joint longer than broad, head at least slightly 

 produced anteriorly; or mesonotum black and strongly 

 punctured 11 



11. Mesonotum entirely black, coarsely 



punctured Epichlorops Becker. 



