P. sarcobati forms a biconvex swelling on the leaves of S. vermiculatus which somewhat resembles the galls formed on Chrysothamnus spp. and Haplopappus spp. by Asteromyia chrysothamni Felt. [these hosts are now mostly in the genus Ericameria, with some exceptions]
”- Raymond J. Gagné: (1969) A tribal and generic revision of the Nearctic Lasiopteridi (Diptera: Cecidomyiidae)©