Triepeolus robustus (Cresson, 1878)
Asclepias subverticillata (A. Gray) Vail, Baccharis glutinosa [= Baccharis salicifolia (Ruiz & Pavón) Pers.], Bahia absinthifolia var. dealbata (Gray) Gray, Eriogonum deflexum Torr., Gaillardia sp., Helianthus annuus L., Kallstroemia grandiflora Torr. ex Gray, Melilotus alba [= Melilotus officinalis (L.) Lam.], Verbesina encelioides (Cav.) Benth. & Hook. f. ex Gray.
Triepeolus flavigradus can be differentiated from T. robustus by the coloration of the transverse bands of pale setae on the metasomal terga (grading posteriorly from yellow to white in T. flavigradus; uniformly pale yellow in T. robustus), as well as by the general shape of the T1 discal patch (quadrate to subtriangular in T. flavigradus; strongly rectangular in T. robustus) and the LLB of T2 (forming a right angle with the ATB in T. robustus, usually absent in T. flavigradus).
MéXICO: Chihuahua, Durango; USA: Arizona, California (locality not specified), Nevada, New Mexico, Texas (Culberson Co., Hudspeth Co., Presidio Co.), Utah.