ART. 20 EEVISION OF THE GENUS WINTHEMIA — EEINHAED 9 



8. Apex of scutellum red 9 



Scutellum and abdomen wholly black, tbe latter highly polished 



except on narrow bases of segments 2 and 3 (Ohio). 



polita, new species (p. 21) 



9. Abdominal hairs long and erect 10 



Abdominal hairs depressed or if partially erect distinctly less 



than one-half the length of marginal macrochaetae 11 



10. Tibiae pale yellow ; third antennal joint black, fully three times 



as long as second (? Massachusetts) tibialis, new species (p. 11) 



Tibiae blackish ; third antennal joint reddish, one and one-third 

 times the length of second (North America) fumiferanae Tothill (p. 12) 



11. Parafrontals golden 12 



Parafrontals cinereous or pale grayish yellow 15 



12. Hind tibiae evenly ciliated at most with one or two longer 



bristles 13 



Hind tibiae with a row of wide-spaced uneven bristles on outer 

 posterior edge ; abdomen slender, segments 2 and 3 pruinose 

 on basal third and shining black on broad apices (Maine). 



vesiculata Townsend (p. 20) 



13. Abdomen gray pollinose 14 



Last three abdominal segments golden pollinose on narrow base 



of each, this color fading to pale yellow and gray apically ; 

 antennae black, third joint fully three times the width of 

 parafacial below (British Columbia) occidentis, new species (p. 22) 



14. Antennae red ; palpi thickened apically ; parafacials moderately 



haired ; mid tibiae usually with one large and one or more 

 smaller bristles near middle on outer front side ; length 10 to 



12 mm. (New England to Mexico) datanae Townsend (p. 29) 



Third antennal joint blackish; palpi slender to tip; parafacials 

 inconspicuously haired ; mid tibiae with a single stout bristle 

 on outer front side near middle; length about 8 mm. (Mary- 

 laud, Indiana) sinuata, new species (p. 25) 



15. Sides of abdomen obviously reddish 16 



Sides of abdomen black, posterior half of intermediate seg- 

 ments shining black ; third antennal joint three to four times 



as long as second ; the black thoracic stripes broad and very 



distinct ; length about 12 mm. (Canal Zone) _ tricolor van der Wulp (p. 42) 



16. Arista of ordinary length thickened on proximal fourth or more 17 



Arista slender to base and uncommonly long; third antennal 



joint broad to apex, fully twice as long as the second ; para- 

 facials bearing only a few inconspicuous hairs; hind tibiae 

 sparsely ciliate with one stouter near middle (Texas). 



intermedia, new species (p. 41) 



17. Cheek in profile at least one-eighth the eye height ; first abdomi- 



nal segment usually with a pair of median marginal bristles ; 

 mid tibiae with two or more bristles on outer front side near 

 middle; parafacials moderately to densely haired (Europe, 



New England) quadripustulata Fabricius (p. 14) 



Cheek in profile almost linear ; first abdominal segment without 

 median marginals ; mid tibiae with a single stout bristle near 

 middle on outer front side; parafacials usually very incon- 

 spicuously haired (North America, widespread) rufopicta Bigot (p. 31) 



