469 

 Wirth and Stone: Diptera 



famous "petroleum fly," breed in pools of crude 

 petroleum and waste oil in California and Cuba. The 

 biology and description of the immature stages have 

 been reported in detail by Crawford (1912) and Thorpe 

 (1931). 



petrolei (Coquillett) 1900. 



Los Angeles County 



Subfamily NOTIPHILINAE 



Tribe ILYTHEINI 



Key to Adults of the California Species of 



Mythea 



1. Coxae and apices of tarsi and rest of legs pale; Ventura 

 County flaviceps Cresson 1916 



— Coxae and femora black; at most 2 fuscous spots in 

 distal 1/2 of submarginal cell 2 



2. Tibiae paler than femora, yellow to ferruginous, at 

 most infuscated medianly; vestiture of face usually 

 more or less cinereous; Los Angeles, Riverside, and 

 San Diego counties caniceps Cresson 1918 



— Tibiae black, at most narrowly pale apically; vestiture 

 of face except foveae, brown; Humboldt to Santa Clara 

 counties spilota (Curtis) 1832 



Tribe PHILYGRIINI 

 Key to Adults of the California Species of Philygria 



1. Wings with fuscous spots on the longitudinal veins, 

 no dark crossbands in 1st posterior cell; Humboldt 

 County opposita Loew 1861 



— Wings with fuscous spots only on the cross veins 



2 



2. Abdomen cinereous except apical segment of male; 

 southern and central California . . . . debilis Loew 1861 



— Abdomen almost entirely shining; San Bernardino 

 County nigrescens (Cresson) 1930 



Key to Adults of the California Species of Nostima 



Last section of 4th vein 4 times as long as preceding 

 section between cross veins; acrostichal area not at 



all shining; Central Valley picta (Fallen) 1813 



Last section of 4th vein at least 5 times as long as 

 preceding section; acrostichal area somewhat shining; 



Riverside and Los Angeles counties 



scutellaris occidentalis Sturtevant and Wheeler 1954 



Tribe HYDRELLIINI 



Genus Hydrellia Robineau-Desvoidy 



(Figs. 14:55^; U:56a,c,d) 



Species of Hydrellia are leaf miners in many species 

 of aquatic and subaquatic plants, especially Pota- 

 mogeton and its relatives (Berg, 1950). H. griseola 

 (Fallen), one of the most common and widespread 

 species, mines in Gramineae, including barley and 

 rice, and the European H. nasturtii Collin in water 

 cress. The tiny Hawaiian species H. williamsi Cres- 





Fig. 14:56. Ephydridae. a,c,d, Hydrellia: a, larva; c, egg; d, 

 posterior segments of larva (a. pi., anal plate; a.s., anal slit; 

 c.w., creeping welt; r.sp., respiratory spine). b,e,f, Notiphila 

 loewi Cress.: b, larva; e, pharyngeal skeleton (h.sc, hypopharyn- 

 geal sclerite; m.h., mouth hook; p.sc, pharyngeal sclerite); f, 

 puparium, attached to root of aquatic plant (a. pi., anal plate; 

 p.s., pharyngeal skeleton; r, root of plant; r.sp., respiratory 

 spine). g,k,l, Neoscatella: g, puparium; k, egg; /, larva, h-/, 

 Brachydeutera hebes Cress., larva: h, anterior spiracle (s.d., 

 spiracular digits); i, posterior spiracle (b, button or scar from 

 previous molt; s, spiracular openings); /', head of adult (a-f, Berg, 

 1950; g-l, Williams, 1938). 



son mines in duckweed (Lemna), having much the 

 same habits as Lemnaphila scotlandi Cresson, a 

 related form of the eastern United States. 



Key to Adults of the California Species of Hydrellia 



1. Palpi black; mesonotum and pleura black 3 



— Palpi yellow; facials in single series;, mesonotum 

 brownish, the pleura grayish; California; mostly low- 

 lands griseola (Fallen) 1813 2 



2. Face brown to black var. obscuriceps Loew 1862 



— Face yellow to golden var. scapularis Loew 1862 



— Face whitish var. hypoleuca Loew 1862 



3. Facials in a single series; face narrow and carinate 

 southern and central California. . .tibialis Cresson 1917 



— Facials in a double series; face broad and flat; Cali- 

 fornia; Transition Zone proclinata Cresson 1915 



