without the 3 lowest families; the second group includes the 3 lowest 

 families of Annulipalpia and the much more recent branch, all Integripalpia. 



Ross constructed the diagram of the further evolution of the Annulipalpia 

 originating from the ancestral form "A" on the basis of pupal and imaginal 

 characters (presence or absence of anal appendages of the pupa, ocelli in 

 the adults, presence or absence of ventral appendages of the male genitalia, 

 etc.). He paid more attention to the larvae as he described the characters 

 of a certain group and its position in the system. 



In contrast to other authors, Ross considers the family Hydropsychidae 

 as relatively primitive and places it between the Philopotamidae and 

 Stenopsychidae. He considers as primitive characters the retention of a 

 free trochantin in the larva and the presence of 2 -segmented ventral 

 appendages in the genitalia of males; however, he stresses the following, 

 highly specialized characters of this family: loss of ocelli in adults and 

 presence of tufted gills and the characteristic tuft of long setae on the anal 

 legs (which is absent in other groups) in the larvae. Ross also considers 

 156 the sclerotization of the meso- andmetanotum of the larvae as characters 

 of specialization. 



Ross considers his family Psychomyiidae (Psychomyiidae Kol. + Poly- 

 centropodidae Ulmer), united because of the loss of ocelli in adults and the 

 1 -segmented ventral appendages of the male genitalia, as the most 

 specialized group of Annulipalpia; he thus disregards the differences in 

 the morphology and biology of the larvae of his combined family (Ross, 

 1944:51-76; 1956:10; Lepneva, 1956:10-15, Figures 1-42). These 

 differences are very marked, however; the larvae of Psychomyiidae 

 (Psychomyiinae of Ross) are primitive microphagous forms, with a 

 predominance of the primary chaetotaxy, which build simple tubular tunnels 

 resembling those assumed to have existed in the ancestral form "A"; the 

 larvae of Polycentropodidae (Polycentropodinae of Ross) are highly 

 specialized forms with a rich secondary chaetotaxy; they are predators 

 which build capturing nets. 



Ross thinks that the most ancient form which developed into the 3 lowest 

 families of Annulipalpia and all Integripalpia is the ancestral form "B"; 

 this form had an undivided last segment of the maxillary palps of the adult 

 and its larvae were free-living, with a dorsal sclerite on abdominal segment 9. 

 The immediate progeny of this most ancient form which became part of the 

 recent fauna are the recent Rhyacophilidae, the larvae of which are free- 

 living and have no portable case. The evolution of the case -bearing habit 

 began with the appearance of ancestral form "C," the larvae of which bore a 

 shieldlike* case and had long anal legs (represented by The Glossosomatidae 

 in the recent fauna). The larvae of the more recent ancestral form "D" are 

 thought to have had short anal legs and to have built sacciform portable 

 cases of various shapes; this form is assumed to have developed into the 

 ancestors of the recent Hydroptilidae. 



In contrast to Martynov, Ross places the later development of the case- 

 bearing habit (appearance of forms with tube-bearing larvae) in a recent 

 period; this developed into the highly differentiated branch Integripalpia, 

 which predominates in the recent fauna. He derives this group from the 



According to Ross (1956:10), the case of these larvae was saddle -shaped ("saddle-case"). 



146 



