FIGURES 18–21. Thremma spp., final instar larvae. 18–19, Thremma sardoum Costa 1884 in Discriminatory matrix for the larvae of the European Thremma species (Trichoptera: Thremmatidae)

FIGURES 18–21. Thremma spp., final instar larvae. 18–19, Thremma sardoum Costa 1884, final instar larva: 18, case, dorsal; 19, case, posterior, showing silken membrane with transverse, ovoid foramen near dorsal border of membrane. 20–21, Thremma anomalum McLachlan 1876: 20, head, frontal; 21, head, ventral (small white number = head seta #8). Scale bars: 0.5 mm.