44 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
13. Large yellowish species; abdomen suffused with Soneacens My 
: aloponotum Dyar. 
GeO w Scales uae ish Gein a te a kee ~~ |viparius Dyar and Knab, 
Somewhat smaller species with little yellow, the abdomen more or less con- 
creteliy handed 2222 <2 3 fs ee Pe ee ee eee ee es ee 14. 
excrucians Walker. 
mutatus Dyar. 
increpitus Dyar. 
mississippii Dyar. 
| classicus Dyar. 
14° Wine scales narrow, NOrMal=== = ee stimulans Walker. 
albertae Dyar. 
mercurator Dyar. 
fitchii Felt and Young. 
| mimesis Dyar. 
[ palustris Dyar. 
Wine scales broad; inflated == 2 ao ian de ae Coane 
15. Terminal abdominal segments with normal pale bands_____~_ vexans Meigen. 
Terminal abdominal segments largely pale scaled______~- cantator Coquillett, 
16. Mesonotum yellow in the integument, with two black spots; scaling incon- 
SPiCUOUS 2-2 SRS Rs es Be Foe ee We es ee bimaculatus Coquillett. 
MeSonotUMEbroOwNs MOL alles Call ele eeee eee  e  e Le 
Aree MESON O CUI an) At KOC we bas SUD ye Tee es eee eae 18. 
Mesonotum dark with two yellow stripes___-__------_-- trivittatus Coquillett. 
Mesonotum: otherwise: marked) 222 ss ae ae ee ee eee 19. 
18. Mescnotum with a broad silvery patch before____infirmatus Dyar and Knab. 
Mesonotum with broad silvery area reaching far back___dupreei Coquillett. 
; : ; : atlanticus Dyar and Knab. 
Mesonotum with narrow median silvery line____ iS 
| eee Dyar and Knab. 
Mesonotum silvery at the sides, dark brown centrally______ triseriatus Say. 
19. Abdomen with continuous, or nearly so, white lateral line__cinereus Meigen. 
Abdomen transversely banded or unbanded, the lateral spots never 
JOINCG 22 23 Soa See ee le Pele fiaion dt yt Oe bee tei a a 20. 
ZOOS Wane Scales mars REC iy: TUCO) OMe Cl ese eset weir eae ppc eee 21. 
\iiabakeo Sree nessinbenlcove an ky Cabeielte ayes saVereielbyy (SVS ke Se al 23. 
21. Mesonotum brown and gray intermixed; wing veins mostly black, with white 
seales subeostalliyzandam cellan eae niphadopsis Dyar and Knab. 
Mesonotum longitudinally striped; wing veins black and white alternat- 
a1) i Aa i na ee Mk fn iar ERC A ate haat Nod 2c on satel ele eed adc as il be/ os 
22. Abdomen with median dorsal abdominal pale stripe__-__ spencerii Theobald, 
Abdomen generally without the median stripe_________ idahoensis Theobald, 
23. Mesonotum typically with central broad undivided dark band_________ 24. 
Mesonotum with divided central dark band or none__________________ 26. 
24. Mesonotum contrastingly yellow at the sides________________________ 25. 
we aes = aestivalis Dyar. 
Mesonotum creamy yellow at the sides__-____________- hiked docoePrnes tata, 
Mesonotum golden or reddish brown at the sides; median stripe sometimes 
divided or mesonotum uniformly dark brown_______-_____ punctor Kirby. 
Mesonotum light yellowish at the sides, with illy contrasted median brown 
De ha a a ee A eR prolixus Dyar. 
25. Yellow lateral lines straight and narrow________--________ aurifer Coquillett. 
Yellow lines broad, narrowed posteriorly__________ thibatlti Dyar and Knab. 
