In Tertiary times the higher Diptera, besides Lepidoptera and Hymenoptera, referable to existing families, become fairly abundant.
So alike in form, colour and mode of flight are those Lepidoptera that when on the wing it is almost or quite impossible to distinguish one from the other, and the resemblance between members belonging to different sub-families cannot be assigned to affinity.
Among the Lepidoptera are gall-forming species belonging to the Tineidae, Aegeriidae, Tortricidae and Pterophoridae.
There are 8 families of Coleoptera, 6 of Orthoptera, 23 of Hymenoptera, 14 of Lepidoptera and 7 of Diptera.
The Coleoptera and Lepidoptera are especially numerous, both in species and individuals.
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.
The standing of the Trichoptera in a position almost ancestral to the Lepidoptera is one of the assured results of recent morphological study, the mobile mandibulate pupa and the imperfectly suctorial maxillae of the Trichoptera reappearing in the lowest families of the Lepidoptera.
The larvae of several nocturnal Lepidoptera feed upon the leaves of the willows, and the trunk of the sallow is often injured by the perforations of the lunar hornet sphinx (Trochilium crabroniforme).
The same style of coloration is found in Coleoptera of the families Cetoniidae and Cantharidae; in Diptera of the families Asilidae, Bombylidae, Tabanidae and Tachinidae; in Hemiptera of the family Reduviidae and in Lepidoptera of the family Zygaenidae.
Towards this Lycoid centre have converged Coleoptera (beetles) of the sub-order Lamellicornia (Copridae), Phytophaga; Heteromera (Cantharidae) and Longicornia; Hemiptera of the families Pyrrhocoridae, Lygaeidae and Reduviidae; Lepidoptera of the families Arctiidae and Zygaenidae; Diptera of the family Asilidae; and lastly Hymenoptera of the families Braconidae, Pompilidae, Crabronidae and Eumenidae.