Several species of Fagaceae (oak and chestnut)-feeding tischeriids occur in Illinois. One species aligns with the genus Tischeria, the rest with Coptotriche.
Tischeria quercitella (Fig. 1) makes a distinctive upperside blotch mine on oaks of the black oak group. According to Braun (1972), it is the only species of the oak-feeding group that constructs a nidus (the circular, central part of the mine seen in Fig. 1) as a pupal chamber within the mine. In the adult, the patch of blackish scales at the tornus of the forewing is diagnostic for T. quercitella, among Fagaceae-feeding tischeriid species that occur in Illinois.
Figure 1. Tischeria quercitella. Adult, and leaf mine on Quercus sp.
Coptotriche citrinipennella (Fig. 2) makes a tightly-rolled mine along the margin of the leaf, on several oak species, including shingle oak, Quercus imbricaria. The blackish patch at the base of each hind wing of the male (shown) is diagnostic for this species.
Figure 2. Coptotriche citrinipennella. Adult, and leaf mine on Quercus sp.
Coptotriche zelleriella (Fig. 3) feeds on several species of oak, Quercus. The male adult (shown) is readily diagnosed by the atypical form of the hind wing, which is unusually broad and apically truncate, with some specialized scales on the anterior margin.
Figure 3. Coptotriche zelleriella. Adult, reared from oak, Quercus sp.
The larva of Coptotriche castaneaeella (Fig. 4) makes a trumpet mine on shingle oak, Quercus imbricaria.
Figure 4. Coptotriche castaneaeella. Adult, and leaf mine on shingle oak, Quercus imbricaria.
Coptotriche probably badiiella (Fig. 5) makes an ovate blotch mine.
Figure 5. Coptotriche probably badiiella. Adult, and larva in leaf mine on oak, Quercus sp.