18. Notopleura setulose; anterior notopleural removed — 

 caudad closer to posterior notopleural 19 



— Notopleura and parafacies bare; anterior notopleural 33. 

 situated in anterior angle of notopleuron, about equi- 

 distant from humeral and posterior notopleural 20 — 



19. Densely cinereous, opaque species; parafacies and 

 cheeks broadly developed Hydrochasma Hendel 



— Shining to dark opaque species; parafacies and cheeks 34. 

 rather narrow (fig. 14:55A;) Discocerina Macquart 



20. Facial series of 2 primaries 21 — 



— Facial series of at least 3 primaries, upper facial on 

 distinct, shining papilla; opaque, densely cinereous 35. 

 species Hecamedoides Hendel 



21. Mesofrons with a pair of strong proclinate bristles in — 

 front of anterior oce liars; 2 pairs of proclinate and 2 

 pairs of lateroclinate frontoorbitals present; Florida 36. 



Paratissa Coquillett 



— Mesofrons bare; 1 pair of proclinate and 1 pair of re- 

 clinate frontoorbitals present 22 — 



22. Mostly opaque cinereous species; facialia with up- 

 curved seta at lower extremity; not California 



Diclasiopa Hendel 



— Mostly shining species; facialia without upcurved seta 37. 

 Ditrichophora Cresson 



23. Second vein closely approximate to costa beyond end — 

 of 1st; posterior cross vein with sharp angle; wings 

 immaculate Clanoneurum Becker 38. 



— Second vein and posterior cross vein normal; wings 

 maculate; not California Discomyza Meigen — 



24. Antennae normal, 1st segment at most slightly exserted, 

 2nd segment trigonal with distinct lobe and spine 



25 39. 



— Antennae elongate; 1st segment exserted, 2nd segment 

 conical, broader apicad, without superior lobe but with — 

 hairlike apical spine; 3rd segment elongate, more or 

 less cylindrical; ocellars approximate and caudad, 40. 

 almost between posterior ocelli . . .Ceropsilopa Cresson 



25. Prescutellar acrostichals present 26 



— Prescutellars absent; 3rd and 4th tergites large and — 

 subquadrate 27 



26. Abdomen ovate with margins revolute; shining, weakly 

 granulose species Trimerinoides Cresson 4 1. 



— Abdomen slender, parallel-sided, with margin sharp; 

 subopaque, granulose species; not California 



Trimerina Macquart — 



27. Frontals well developed; ocellars cephalad of posterior 42. 

 ocelli; halteres white 28 



— Frontals weak, hairlike; ocellars small, set between — 

 posterior ocelli (fig. 14:55<7); halteres usually dark; 

 wings yellowish with dark bases .. J'lagiopsis Cresson 



28. Face with 3 or more closely set facials, lower part 43. 

 flattened and wrinkled; supra-alar bristle well developed 



not California Rhysophora Cresson — 



— Face with 1 or 2 facials; supra-alar absent or minute 



29 44. 



29. Face with 1 strong facial (fig. 14:55/); not transversely 

 tumid in middle but sometimes weakly carinate longi- — 

 tudinally 30 45. 



— Face with 2 strong facials, and transversely carinate 

 or tumid in middle Helaeomyia Cresson 



30. Fore basitarsi black and thickened; middle of face 

 slightly carinate with fine transverse wrinkles, facial 



at or above midfacial profile Leptopsilopa Cresson — 



— Fore basitarsi normal; middle of face smooth and con- 46. 

 vexy facials below midfacial profile . . . P silopa Fallen 



31. Posterior notopleural removed from ventral margin of 

 notopleuron 32 



— Posterior notopleural in normal position, close to — 

 ventral margin of notopleuron 36 



32. Face broad and greatly swollen, with broad mouth 

 opening (fig. 14:55p); wings uniformly spotted (fig. 

 14:550) (ILYTHEINI) 33 47. 



465 

 Wirth and Stone: Diptera 



Face narrow or if broad is concave; wings not uniformly 



spotted (HYDRIN1NI) 34 



Second vein long, subparallel to costa; 2nd costal 



section over twice as long as 3rd Ilythea Haliday 



Second vein short, mostly straight to costa; 2nd costal 

 section not twice as long as 3rd (fig. 14:55o); not 



California Zeros Cresson 



Face narrow, not concave and if prominent the epistoma 



is receding 35 



Face broad, concave, with prominent epistoma; arista 



long haired; not California Lemnaphila Cresson 



Arista bare; presutural dorsocentral present 



Philygria Stenhammar 



Arista short- to long-haired; presutural dorsocentral 



absent Nostima Coquillett 



Ocellars stronger than postocellars which are always 

 weak; eyes bare; humerals and supra-alars strong 



37 



Ocellars seldom as strong as postocellars, usually 

 much weaker; eyes pilose; humerals and supra-alars 

 usually weak, hairlike (fig. 14:55A) (HYDRELLIINI) 



Hydrellia Robineau-Desvoidy 



Mid-tibia with 1-4 erect extensors; dull species (NOTI- 



PHILINI) 38 



Mid-tibia without erect extensors; shining black species 

 (fig. 14:55» (TYPOPSILOPINI). . . Typ op silopa Cresson 

 Costa extending to 4th vein (fig. 14:54;'); antennal spine 



weak (fig. 14:54t) 39 



Costa not reaching to tip of 4th vein (fig. 14:556), rarely 

 beyond 3rd; antennal spine strong (figs. 14:54A; 14:55a) 



40 



Small cinereous species (2-2.5 mm.) without mesonotal 



setulae; sternopleural absent Oedenops Becker 



Larger dark species with well-developed mesonotal 



setulae and strong sternopleural Paralimna Loew 



Facial bristles large and situated close to parafacies; 

 fronto5rbitals very strong (fig. 14:55a); dark brown to 



black species Dichaeta Meigen 



Facials hairlike and well removed from parafacies; 

 frontoorbitals weak (fig. 14:54A); ochraceous to cinere- 

 ous species Notiphila Fallen 



Eyes hairy; antennae small, inserted far apart in 

 cavities, arista atrophied (fig. 14:54/) (LIPOCHAETINI) 



Lipochaeta Coquillett 



Eyes bare; antennae normal, arista well developed . . 42 

 Mouth opening large and gaping, clypeus transversely 



elongate and exposed (PARYDRIN1) 43 



Mouth opening small to moderately large; clypeus not 

 prominent (exposed but tonguelike in Ochthera and 



Pelina) (HYADININI) 44 



Costa extending to 3rd vein; arista with long dorsal 



rays (fig. 14:54/) Brachydeutera Loew 



Costa extending to 4th vein; arista bare (fig. 14:55m) 



Parydra Stenhammar 



Fore legs raptorial, their femora greatly enlarged, their 

 tibiae ending in a spur (fig. 14:55n). .Ochthera Latreille 



Fore legs normal, femora slender 45 



Arista with long hairs; head trigonal in cephalic aspect x 

 face subconically or hemispherically gibbous above; 

 abdomen subglobose, lateral margins revolute, 4th 



tergite not lengthened; not California 



Gastrops Williston 



Arista bare or pubescent; head not trigonal 46 



Wing with 2nd vein long, 2nd costal section about 3 

 times as long as 3rd; face flat or carinate, not medianly 

 prominent; 3rd antennal segment rounded at apex above 



Pelina Haliday 



Wing with 2nd vein short, 2nd costal section less than 

 twice as long as 3rd; face with low conical median 

 prominence; 3rd antennal segment usually angulate at 



apex above 47 



Abdomen not convex above, 4th tergite not lengthened, 

 never longer than 5th Hyadina Haliday 



