APPENDIX.
333
numerous silvery hairs; wings with fuscous nervures; a fuscous band including nearly all the radial cellule, and not reaching the posterior angle; tip slightly margined with fuscous; posterior thighs and tibiae at base rufous; abdomen sessile, first and second segments rufous.
Length about three-tenths of an inch.
2. P. marginatum. Black; wings dusky, with a broad, darker posterior margin; abdomen sessile, first and second segments rufous.
Inhabits North-west Territory and Missouri.
9 The terminal dark margin of the wings is so broad as to reach almost to the terminal cubical cellule, and passes round on the costal margin to the origin of the radial cellule; on the inferior wings is also a broad, terminal, darker margin.
Length two-fifths of an inch.
Very similar to the preceding, but manifestly distinct by the above characters.
CEROPALES, Latr.
1. Cfasciata. Black; thorax and tergum spotted and banded with pale yellowish; feet ochreous, tarsi pale yellow.
Inhabits United States.
Front, labrum, and orbits yellow, the latter interrupted above; thorax punctured; anterior margin, a spot each side near the head, a longitudinal, abbreviated, central line, yellow; scutel with a spot on the disk, and another transverse one beneath its tip, yellow; wings immaculate, nervures blackish; pectus with a yellowish spot over the intermediate and another over the posterior feet; coxse, first joint with a dilated yellow line; posterior feet elongated; ter~
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