More recently the subdivision of the Linnean Neuroptera has been carried still further by the separation of the caddis-flies and scorpion-flies as distinct orders (Trichoptera and Mecaptera respectively), and by the withdrawal of the " Pseudo-neuroptera " from the Orthoptera - with whose typical families they have little in common - and their division into a number of small orders.
At the base of each wing projects a dorsal lobe - the jugumand the neuration is predominantly longitudinal, resembling so closely that of the lower Lepidoptera (q.v.) that a nearer relationship of the Trichoptera to that order than to any group of the old Linnean Neuroptera is certain.
Fossil Trichoptera occur in rocks of Liassic age.
Frequently the whole of the Trichoptera are included in a single family, but most special students of the order recognize seven families.
In all Trichoptera the maxillary palps of the female are fivesegmented.