172 University of California Vublications. [Entomology 



Subfamily HYDRELLINAE. 



1 . Eyes thickly pubescent 2 



Eyes sparsely pubescent or bare 4 



2. Back of thorax without evident machroch.-i'tiv, autennal arista 



bare or feebly pubescent Glenanthe Haliday 



Back of thorax with distinct dorso-central iiiachrochaetse 3 



3. Pace convex Hydrellia Rob.-Desv. 



Face slightly concave Nostima Coquillett 



4. Costal vein extending to third longitudinal Axysta Haliday 



Costal vein extending to fourth longitudiu tl T) 



5. Thorax with three pairs of dorso-central and two noto-pleural 



machrochsetae. sides of face without bristles 



Philygria Stenhammar 



Thorax with only one pair of dorso-central machrochaitas and 

 always one noto-plenral machrochiieta, sides of face with 

 bristles Hyadina Haliday 



Subfamily EPHYDRINAE. 



1 . Clypeus projecting 2 



Clypeus hidden 9 



2 . Oral opening small 3 



Oral opening large 7 



.">. Front femora much thickened, first posterior cell narrowed at the 



border of the wing Ochthera Latreille 



Front femora moderately thickened, third and fourth veins 



parallel Ochtheroidea AVilliston 



Front femora not thickened 4 



4. Hind legs long, extremity of proboscis bent back to form a hook 



Ectropa Schiner 



Hind legs not lengthened, extremity of proboscis not hook-shaped "> 



5. Anterior part of mesonotum without bristles. ... Pelina Haliday 

 Anterior part of mesonotum with bri.stles G 



G. Third .joint of ant<mn;p with an obtuse carina abo\e 



Lytogaster llecker 



Third .ioint of antenmie nearly round, large Domina Hutton 



7. Costal vein reaches to third longitudinal. .. Brachydeutera Low 

 Costal vein reaches to fourth longitudinal 8 



8. Oral margin with several erect bristles latrrally, auxiliary vein 



distinct from the first longitudinal throughout, thorax with 



five distinct dorso-central machrochsetse. .Halmopota Haliday 



Oral margin without bristles laterally, auxiliary vein coalescing 



with the first longitudinal except at its proximal end, thorax 



with only two to three dorso-central machrochsetae 



Parydra Haliday 



9. Claws almost straight, pulvilli indistinct Ephydra Fallon 



Claws curved, pulvilli distinct Ki 



10. Costal vein reaches to third longitudinal 11 



Costal vein reaches to fourth longitudinal 12 



11. Thorax with only a pair of humeral machroch.ieta' in front.... 



J Scatophila Ilecker 



Thorax with four rows of bristles extending to the anterior part 

 Pelomyia Williston 



