Caddis-flies (Order Trichoptera) are small insects closely related to Butterflies (Order Lepidoptera). Adult Caddis-flies are found in the vicinity of freshwater habitats from springs and creeks to streams, lakes or swamps where, during daytime, they hide in nearby vetetation, but fly during evenings or at night. The eggs are deposited in water where the larvae hatch, then build retreats, nets or portable cases.
According to their case-making behaviour patterns caddis-fly larvae have been classified into five groups. More than 70% of 163 species described in this handbook are endemic to Tasmania; the remainder are shared with the Australian mainland.