This species and clavata are indistinguishable. Galls of the two species have the same general form except that that of pilosa has a thick covering of hair (Fig. 2e), while that of clavata is smooth (Fig. 2g),
β- Raymond J. Gagne, GL Waring: (1990) The Asphondylia (Cecidomyiidae, Diptera) Of Creosote BushΒ©