REPORT OF ENTOMOLOGIST. 73 
44. Flies in June; a good deal of yellow on head and thorax 
(Colo.).crawfontf Ckll. 
Flies in May; no yellow on head and thorax (Colo.).. eoHinslana Ckll. 
45. Metathorax ferruginous and black, without any yellow; cJ's...46. 
Metathorax entirely black..47. 
Metathorax black with rather small light spots; lateral face- 
marks broad, but not or hardly going above level of an¬ 
tennae; apical plate of abdomen more or less notched; tfs .51. 
Metathorax with two large yellow (or yellow and red) spots.52. 
46. Metathorax black without much ferruginous; scutellum and 
postscutellum yellow; apical plate of abdomen entire; flies 
yellowish; size smaller; apical plate of abdomen deeply 
47. Size larger; tegulae yellow; apical plate of <9 abdomen en¬ 
tire (Colo., Wyo.).superba Cress. 
Size much smaller.48. 
48. Tegulse yellow (Colo ).lutsopieta Ckll. 
Tegulse ferruginous.49. 
49. Head and thorax with much red; larger; flies in sping; 9 (N. 
M.).placiiensis Ckll. 
Head and thorax without red; smaller; apical plate of abdo¬ 
men notched; c?s.50. 
50. Antennae very long, denticulate beneath; fourth joint very 
long, at least twice as long as third on upper side (N. M., 
Colo.). fragilis Cress. 
Antennae not so long, not denticulate beneath; fourth joint 
not nearly twice length of third on upper side (Colo. )pa!lid©Ha Ckll. 
51. Supraclypeal mark present; metathorax with four reddish or 
yellowish spots, two being on the enclosure (Mont.) .. eSrosSi Ckll. 
Supraclypeal mark absent; metathorax with two small oval 
yellow spots (Colo.). giifettei Ckll. 
52. Basal nervure meeting transverse-medial or falling short of 
it; species (at least vincta and zebrata) flying in late summer 
and early fall .53. 
Basal nervure beginning decidedly (often greatly) basad of 
transverse-medial.54. 
53. Apical plate of ^ abdomen entire; mesothorax of <$ wholly 
black, or with very narrow reddish lateral margins, of V 
black or red and black (Colo.). vincta Say. 
Apical plate of $ abdomen slightly notched; mesothorax of 
cT with yellow lateral margins,of 9 red (Colo.,N. M.) zebrata Cress, 
unknown; mesothorax of 9 black with yellow lateral mar- 
gins;thorax narrower than in zebrata; yellow of metathorax 
intruding on enclosure (which is not the case in vincta or 
zebrata); third antennal joint considerably shorter than 
fourth (it is considerably longer than fourth in zebrata and 
vincta) (Colo.). perivincta Ckll. 
54. Mesothorax black, with the anterior lateral corners red; api¬ 
cal plate of abdomen truncate, not appreciably emargin- 
ate; sides of metathoracic enclosure yellowish; $ (Colo.) 
. agynia Ckll. 
Mesothorax red, with or without a black band; 9 s.. 55. 
55. Flagellum strongly blackened at end, mesothorax with a 
broad median black band; scutellum yellow without a 
median dark stripe or shade; basal nervure a short dis¬ 
tance basad of transverse-medial; third antennal joint a 
little shorter than fourth (Colo.). perivincta var. semirufula Ckll. 
Flagellum red, not blackened at end.56. 
56. Ventral surface of abdomen yellow, with narrow red bands; 
scutellum at least mostly yellow.57. 
