but not in California, as biting man, and it is likely 

 that wild hosts, particularly birds, form their most 

 important source of food. The immature stages are 

 aquatic, the larvae often occuring in tremendous con- 

 centrations along stream, lake, or pond margins, in 

 tree holes, or in polluted puddles and ditches. Foote 

 and Pratt (1954) have recently published a well- 

 illustrated revision of the species of the eastern 

 United States. Hill (1947), Williams (1951), and Kettle 

 and Lawson (1952) have contributed valuable papers 

 on the biology of Culicoides. 



Key to the California Species of Culicoides 

 Fema les 



1. Wing uniformly colored, without light or dark markings; 

 small, dark pruinose species 2 



— Wing with at least 1 dark and usually 2 or more light 

 spots 5 



2. Mesonotum uniformly colored, without definite pattern 

 3 



— Mesonotum with distinct pattern 4 



3. Mesonotum polished black; Mono, Plumas, and San 

 counties monoensis Wirth 1952 (part) 



— Mesonotum pruinose brown brookmani Wirth 1952 



4. Mesonotal pattern largely bluish pruinose, an irregular, 

 median, dark line and 2 very irregular, broken lateral, 

 dark patches; southern and central California 



hieroglyphicus Malloch 1915 



— Mesonotum mostly darker, the light pruinose markings 

 largely confined to 2 narrow submedian stripes; northern 



and central California jamesi Fox 1946 



coast Range tenuistylus Wirth 1952 



northern and central California 



unicolor (Coquillett) 1905 



5. Second anterior radial cell wholly or mainly included 

 in a light spot (fig. 14:38a) 6 



— Second anterior radial cell mainly included in a very 

 dark spot 10 



6. Mesonotum uniformly colored, without definite pattern 

 7 



— Mesonotum with distinct pattern, the dark markings 

 large and distinct \ 9 



7. Wing macrotrichia scanty, at tip of wing only; smaller 

 species; northern counties and Sierra Nevada 



obsoletus (Meigen) 1818 



— Wing covered almost entirely with macrotrichia; larger 

 species 8 



8. Third palpal segment slender; mesonotum with 3 dis- 

 tinct, very narrow, dark striae; larger brown species, 

 less hairy; eyes separated by width of at least 1 facet; 

 Humboldt and Marin counties .tristriatulus Hoffman 1925 



— Third palpal segment short and swollen; mesonotal 

 striae very indistinct; smaller grayish, hairy sub- 

 species; Imperial and San Bernardino counties 



cockerellii saltonensis Wirth 1952 



9. Mesonotal pattern typically with 2 oblique, lateral, 

 dark-brown spots (fig. 14:386); large, slender sub- 

 species; northern California 



cockerelli cockerellii (Coquillett) 1901 



— Mesonotal pattern typically with front and sides dark, 

 the prescutellar area pruinose gray with angularly 

 twice-stepped anterior margin; shorter, robust species; 

 widespread in California; breeds in tree holes 



luteovenus Root and Hoffman 1937 



10. Wing with only anterior radial cells dark, remainder 

 unicolorous gray; mesonotum shining black; small 

 black species monoensis Wirth (part) 



— Wing with 2 or more light spots in addition to dark 

 anterior radial cells; mesonotum not shining black 



11 



11 

 12 



13. 



14 



15 



16 



17 



18 



1!) 



20 



433 

 Wirth and Stone: Diptero 



Mesonotum without dfstinot pattern 19 



Mesonotum with distinct color pattern lfi 



Wing with only 1 or 2 light spots, on r-m cross veto 



and just behind 2nd anterior radial cell 13 



Wing with light areas on posterior margin in addition to 



2 light costal spots 14 



Wing with 2 light spots, at cross vcm and just beyond 

 2nd anterior radial cell; color difference- in wing 11 

 macrotrichia scattered and abundant; Shi ta County 



unicolor (Coquillett)(part) 



usingeri Wirth 1952 



Wing with 1 light spot just beyond 2nd anterior radial 

 cell owing to absence of macrotrichia; these arranged 

 in rows in cells M, and M a ; Ventura, Riverside, and 



San Diego counties 



copiosus Root and Hoffman 1937 (part) 



Wing almost devoid of macrotrichia, a few at wing 

 tip and along ends of veins; small species, 1 mm. or 



less in length; Kern and Tulare counties 



reevesi Wirth 1952 



Wing with abundant macrotrichia; larger species, 



more than 1.5 mm. in length 15 



Mesonotum dark brown, contrasting strongly with the 

 yellowish abdomen; Mohave Desert ..mohave Wirth 1952 

 Mesonotum and abdomen grayish brown, not contrasting; 



breeds in tree holes unicolor (Coquillett) (part) 



widespread utahensis Fox 1946 



Shasta County palmerae James 1943 



Mesonotum marked with many small dark spots, each 

 with a hair arising from center; widespread in California 



variipennis (Coquillett) 1901 



Mesonotum marked with a few large dark stripes, usu- 

 ally more or less cross connected 17 



Wing with 3 light spots along anterior margin between 

 2nd anterior radial cell and tip of vein M,; Mono, Kern, 



and Ventura counties stellifer (Coquillett) 1901 



Wing with only 2 light spots between 2nd anterior radial 



cell and tip of vein M, 18 



Hind tibia with small subbasal light band, the tip dark 



19 



Hind tibia with small subbasal and broad subapical 

 light bands; cell R 5 of wing with light spots at base 



and extreme apex; widespread 



haematopotus (Malloch) 1915 



Second light spot in cell R 5 double; median dark stripe 

 of mesonotum connected with lateral dark stripes; 



widespread baueri Hoffman 1925 



Second light spot in cell R 5 single; median dark stripe 

 of mesonotum not connected with lateral dark stripes 



20 



.Larger species; wing pattern includes light spots in 

 base of cell Mj and middle of cell M 2 ; widespread 



crepuscularis (Malloch) 1915 



Smaller species; wing pattern includes light spots on 



base of vein M, and middle of vein M a 



copiosus Root and Hoffman (part) 



Male Genitalia 



1. Ninth tergite rounded at tip, apicolateral processes 

 absent or very small, not surpassing apex of tergite 

 (fig. 14:38c) 2 



— Ninth tergite of various shapes, apicolateral processes 

 well developed, surpassing apex of tergite 5 



2. Inner side of basistyle not spinose; apicolateral proc- 

 esses of 9th tergite absent, apex of 9th tergite blunt; 

 ventral root of basistyle much longer than dorsal root 



obsoletus (Meigen) 



- Inner side of basistyle with patch of stout spines; 

 apicolateral processes present but small; ventral and 

 dorsal roots subequal (fig. 14:38c) 3 



3. Tip of aedeagus with a distinctly elongated, slender 

 point arising from the broad body . tristriatulus Hoffman 



luteovenus Root and Hoffman 



