9. Basal lobe of basistyle with 1 short stout bristle, a — 

 long curved one and a dense group of slender bristles: 

 apical lobe of basistyle with a group of bladelike 

 setae; claspette stem not sharply angled near middle 7 

 (fig. 14: 16^) dorsalis (Meigen) 



— Basal lobe of basistyle with 2 stout inner bristles 

 close together and a long outer spine with a few 

 inconspicuous bristles in between; apical lobe of 

 basistyle with bristles of varying length; claspette — 

 stem sharply angled near middle. . .pullatus (Coquillett) 



10. Claspette filament with a sharp angle near base of 

 concave edge 11 



— Claspette filament without sharp angle near base of 8. 

 concave edge 12 — 



11. Claspette filament only a little wider at basal 1/3 than 

 apical diameter of claspette stem 9 



fitchii (Felt and Young) 



— Claspette filament expanded at basal 1/3 to about 

 twice the apical diameter of claspette stem 



sticticus QAeigen) — 



ventrovittis Dyar 



12. Claspette filament with a median sharp angle or retrorse 

 point on convex side 13 



— Claspette filament rather evenly convex at middle of 

 one side 14 10 



13. Claspette filament with expansion forming an acute 

 angle; basal lobe of basistyle well separated from — 

 apical lobe squamiger (Coquillett) 



— Claspette filament with expansion forming an obtuse 11 

 angle; basal lobe of basistyle reaching almost to 

 apical lobe flavescens (Mueller) 



14. Claspette filament markedly broadened at basal 1/3 

 cataphylla Dyar 



— Claspette filament slender, not markedly broadened at 

 basal 1/3 15 — 



15. Apical lobe of basistyle with numerous short, curved, 

 broadened setae; basal lobe of basistyle with stout 

 spine broadly curved from near middle; claspette dis- 12 

 tinctly shorter than dististyle hexodontus Dyar 



— Apical lobe of basistyle with bristles only; basal lobe 

 of basistyle with stout spine bent or curved near apex; 

 claspette about as long as dististyle 



communis (Degeer) 



Larvae 



Pecten terminating in 1 or more rather widely separated 



teeth 2 



Pecten teeth rather evenly spaced 8 13, 



Siphon with detached pecten teeth distad of insertion 

 of siphon tuft; upper and lower head hairs almost 



invariably single 3 



Siphon with pecten row ending before insertion of — 



siphon tuft 4 14, 



Siphon with only a single pair of tufts; dorsal pre- 

 apical spine straight; Sierran meadow species, usually — 



in full sun cataphylla Dyar 



Siphon with a small tuft above pecten row basad of 15 

 main tuft; also a single or double hair inserted dorsally 

 and subapically on siphon; dorsal preapical spine 



curled at end; Coast Range meadow species 



bicristatus Thurman and Winkler 



Comb of at least 20 scales; lateral hair of anal segment 

 more than 1/2 as long as saddle; typical comb tooth 

 with a strong central thorn and weak side teeth; flooded 



meadows flavescens (Mueller) 



Comb of less than 20 scales 5 — 



Pentad hair 2 located obliquely ventral to hair 1 and 

 about on a line between 3 and 1; upper and lower head 



hairs not both single 6 



Pentad hair 2 directly posterior or dorsoposterior to 16 

 1; upper and lower head hairs usually single, rarely 



double 7 



Lower head hair with 4 to 8 branches; upper with 5 to 

 9; Sierran meadow or pine needle pools in partial or 

 dense shade cinereus Meigen 



397 

 Wirth and Stone: Diptera 



Lower head hair single to triple, upper with 2 t<> 1 

 branches; river overflow pools or sometimes in irn 



pastures Damans (M<-ig<-n) 



Anal segment completely ringed by saddle; dorsal 

 preapical spine of siphon about as long as middle 

 pecten tooth; pecten extending about \\/\ of siphon tube 



length; flooded meadows and irrigated pastures 



nigromaculis (Ludlow ) 



Anal segment not completely ringed by saddle; dorsal 

 preapical spine of siphon inconspicuous; pecten ex- 

 tending not more than 2/3 of siphon tube length; Sierran 



meadows ventrovittis Dyar 



Anal segment completely ringed by saddle 9 



Anal segment not completely ringed by saddle (fig. 



14:17/) 10 



Comb of many apically fringed scales in a patch; upper 

 and lower head hairs single; basal diameter of siphon 

 greater than dorsal length of saddle; coastal marshes 



of southern California taeniorhynchus (Wiedemann) 



Comb usually with 5 to 7 thornlike scales ir. a row; 

 upper head hair single to triple; lower single or double; 

 basal diameter of siphon about equal to dorsal length 



of saddle; Sierran pools in shade or sun 



hexodontus Dyar 



Lateral hair of anal segment as long as or longer than 



saddle, sometimes with 2 or more branches 11 



Lateral hair of anal segment shorter than saddle and 



usually single 13 



Pentad hair 2 located obliquely ventral to hair 1 and 

 about on a line between 3 and 1; typical comb scale 

 slender and with a row of bristles across rounded or 

 truncate apex; gills large, usually about as long as 



siphon; hair d large and multiple; tree holes 



varipalpus (Coquillett) 



Pentad hair 2 located directly posterior or dorsoposter- 

 ior to 1; gills much shorter than siphon; head hair d 



minute 12 



Siphon tube about 4 times as long as its greatest 

 diameter; terminal pecten tooth almost as long as apical 

 diameter of siphon tube; upper head hair with 3 or 

 more branches (usually 4), lower with 2 or more (usually 



3); Sierran meadow or tule-filled pools 



fitchii (Felt and Young) 



Siphon tube less than 3 times as long as its greatest 

 diameter; terminal pecten tooth about 1/2 as long as 

 apical diameter of siphon tube; upper and lower head 

 hairs single to triple (upper usually double or triple, 



lower usually double); brackish coastal marshes 



squamiger (Coquillett) 



Anal segment about 7/8 ringed by saddle; lower head 

 hairs single or double, upper usually with 2 or more 



branches; shaded river overflow pools 



sticticus (Meigen) 



Anal segment 1/2 to 4/7 ringed by saddle 14 



Upper head hair with 5 or more branches, lower with 



3 or more; Sierran meadows pullatus (Coquillett) 



Upper head hair with fewer than 5 branches, lower with 



fewer than 3 15 



Dorsal microsetae toward apex of saddle well devel- 

 oped, more than twice as long as those toward base 

 of saddle and longer than diameter of setal ring at 

 base of lateral hair of anal segment; head hairs with 

 2 to 4 branches or sometimes all single (especially in 

 northeast California); siphon tuft inserted before middle 

 of siphon tube; mostly in flooded grassy pools, common 

 in the Sierra, less so at lower elevations down to sea 



level incre pitus Dyar 



Dorsal microsetae toward apex of saddle weakly devel- 

 oped, less than twice as long as those toward base of 

 saddle and about as long as diameter of the setal ring 



of lateral hair 16 



Dorsal preapical spine of siphon inserted less than its 

 length from apical margin of siphon tube; siphon tuft 

 often inserted at or beyond middle of inner surface of 

 siphon tube; gills usually short but sometimes longer 

 than anal segment; upper and lower head hairs usually 

 single, sometimes double or upper rarely triple; irri- 



