trevorsless 的鑑定

Browsing through Molly Rightmyer's 2008 monograph on this genus suggests possibility of T. pectoralis -- rather long setae sticking out from mesepisternum, ruling out helianthi and cressonii (photo 3); and distinct crescent of white hair at base of pseudopygidial area (again ruling out helianthi, but not cressonii).

The Discover Life key also points to T. pectoralis based on the following traits: most integument is dark; legs are black-brown or mixed black-brown and red-orange; longitudinal lines on scutum don't clearly touch anterior edge; T1 bands are parallel and black space is wide; T2 lateral and apical bands form weakly acute angle; mesepisternum has erect simple hairs (length either equal or half the diameter of ocelli); pseudopygidial area is quadrilateral or oval; and hair bands are pale yellow, not greyish-white. I am least sure about the last trait, but choose pale yellow after seeing the photos in Rightmyer's monograph.