AMERICAN DIPTERA. 259 



SYNOPSIS OF SPECIES. 



WESTERN SPECIES*. 



f Scutellum rather convex above, its posterior margin rounded; 

 surface black, sometimes pruinose at base only, and 

 beset with long pile; legs densely pilose, and rather 

 I I stout (except in princeps, where they are more slen- 

 der) 2. 



Scutellum more or less flattened above, surface densely grayish 

 pruinose; legs moderately hairy, and not very stout 

 (rather hairy in rattps) 4. 



Hind tibiae more or less reddish in the middle (except in prcBpes)..3. 



All the tibiffi entirely black priiiceps J* ; cretaceus $ ; 



longinianiis (^ 9 ; rufotarsus (^ $ . 



Front tarsi of the male ornamented with dense silvery pile; 

 middle tarsi with brushes of black bristles. 

 callipedilus cT — ; cymbalista J* 9 ; plaiisor 

 (^ 9; prsepes J*, 9- 



Front tarsi and tibije not ornamented as above, although pul- 

 cher has white pile on the fore tarsi.... niontanus (J^ 

 9 ; leucozoims 9 ; aiirifex (^ 9 ; rtasyllis c? ; 

 dasylloides cJ*, pvilcher (^ 



Abdomen black, with spots or cross-bands on the posterioi mar- 

 4. -^ gin of the segments 5. 



Abdomen gray; with black spots rattus. 



Legs reddish (femora black in dubius)iM'ofnsns S" 9 ; tliil>ius 9 . 



Legs black evidens c? 9; rejectiis cJ'; mig-ator cT 9; 



nigricolor, postiviis, siidator cP 9 • 



Aberrant species ceriissatiis (J* 9; gibber 9; nebiilo 9; 



varij)eiiiiis cf 9 • 



3.^ 



C Abdomen! with long, erect, yellow pile; length 16-18 mm. 



dasyllis, dasylloides. 



Abdomen without such pile; smaller species 2. 



Antennal style as long, or nearly as long, as the third segment. 3. 



Antennal style much shorter than the third segment 4. 



First basal cell of wing without brown spots iiebvilo. 



First basal cell of wing with two brown spots varipeniiis. 



Third antennal segment red 20. 



Third antennal segment black 5. 



Hind tibiae more or less red in the middle (black in prcepes) 6. 



Hind tihise black 12. 



* Does not include tibialis Coq. and maculosis Coq. based on females 

 only, near plausor and rejectus respectively. 



t Does not include dubius, gibber, maculosis, nigricolor or tibialis. 

 all of which are not well known to me, and based only on single female 

 specimens, except tibialis, based on three females. 



TRANS. AM. ENT. SOC., XXXV. JULY, 1909 



