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lower Annulipalpia (Hydroptilidae) and places the ancestral form of the 

 tube bearers ("E") far away from the 3 preceding ancestral forms which 

 developed into the lower Annulipalpia. Ross based the later evolution and 

 differentiation of Integripalpia in his phylogenetic scheme on the characters 

 of the adults; he gave fragmentary data on some characters of the larvae in 

 a few cases. He divided the Integripalpia into 2 groups shown in his scheme 

 as 2 differentiated branches which diverged early. In the recent fauna, he 

 included the Phryganeidae, Limnophilidae, Plectrotarsidae, Goeridae, 

 Brachycentridae and Lepidostomatidae in the first group; he includes all 

 other families which he considered more specialized in the second group. 



Ross does not deal with the factors of the environment; he discusses the 

 relation of Trichoptera to the water temperature in a special genetic scheme 

 constructed like his general phylogenetic scheme. Ross considers the whole 

 order, except the Xiphocentronidae, as originally cold-loving from the most 

 ancient times to the Cretaceous;* only later, in certain families, small 

 branches of ecologically specialized forms appeared which became 

 adapted to well- warmed (stagnant!) water bodies. 



The eclectic character of Ross's scheme, which is based (except its 

 hypothetical root) on isolated, not coordinated morphological characters of 

 the different stages of development, makes it appear artificial. This 

 explains the difference of opinion and contradictory data on the phylogenetic 

 relationships of the families. For example, the Hydropsychidae have highly 

 specialized larvae (more specialized than those of the other Annulipalpia); 

 their adults have no ocelli, fly well, occur in large numbers and sometimes 

 "flood" their habitat. This family is artificially placed between the most 

 primitive Philopotamidae and Xiphocentronidae on one hand, and the 

 Stenopsychidae on the other. This classification separates the closely 

 related families Philopotamidae and Stenopsychidae and also the Xipho- 

 centronidae and Psychomyiidae (Psychomyiinae of Ross), the larvae of which 

 are closely related as shown recently (Edwards, 1961). This position of 

 the higher Annulipalpia in Ross's scheme, as well as the relative position 

 of all the other family groups of Annulipalpia which were derived by Ross 

 from the ancestral form "A" (except the Philopotamidae), is completely 

 artificial. 



The difficulty of coordinating, in the same phylogenetic scheme, the 

 evolution of adult Trichoptera and of their preimaginal stages arises from 

 their adaptation to different conditions, either in the air or in the water. 

 The explanation for the causes of evolution of different ontogenetic stages 

 of insects should probably be looked for in the conditions of the environment 

 and in the changed conditions in water bodies; the larvae develop at the 

 bottom of water bodies; the winged insects live on the banks of water bodies, 

 among the terrestrial fauna. Coordination of the causes of evolution of a 

 species in either of the foregoing stages may have a different character; 

 in some cases (Hydropsychidae) those which live in large streams in the 

 plains evolve progressively in both stages; the larvae at the bottom of the 

 river and the adults on the banks of the river predominate, sometimes 



flooding" a locality. In other cases (Rhyacophilidae) progressive evolution 

 is present only among the larvae and not among the adults; these adults 

 lead a concealed life during their short existence (often only a few days), 



* In fact, this represents inhabitants of flowing water bodies originating from springs or from mountains. 



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