FIGURE 94. Larva of Brachycentrus 

 waiting for prey (after Murphy) 



The larvae of Apataniinae, which are very small, live on stones, on the 

 open shore of lakes, in brooks and springs, where they feed on plant over- 

 growths of stones; in addition to algae, the high nutritive value of these 



overgrowths is provided by the bacterial and 

 fungal flora among the algae and on the 

 surface of stones; in Lake Baikal, species of 

 the tribe Baicalinini develop in large numbers 

 on this food, covering the stones sometimes 

 almost completely. The larvae of Apataniinae 

 sometimes use their elongate spatulate 

 mandibles to scrape the incrustations from the 

 stones; these mandibles are a convergent 

 character present in different, often remote 

 groups of caddis flies with a similar mode of 

 life and method of feeding; in the subfamily 

 Limnophilinae, such scraping mandibles are 

 pre sent in the larvae of Ecclisopteryx 

 guttulata which feeds on overgrowths of 

 plants; in the suborder Annulipalpia such 

 mandibles are present in species of Glosso- 

 somatidae. 



The feeding of the larvae of Goeridae, 

 Lepidostomatidae, Brachycentridae and 

 Sericostomatidae (formerly united in the 

 family Sericostomatidae) has not been 

 sufficiently studied. The view on the exclusively phytophagous feeding of the 

 larvae of these families (Siltala, 1907:21—22) based on examination of the 

 intestine of a number of larvae cannot be applied to the family Brachy- 

 centridae, the larvae of which feed both on vegetable and animal food. In 

 the intestines ofGoera pilosa, Lithax obscura, Silo nigricornis 

 and S. pallipes (Goeridae) algae and plant fragments were found; in the 

 intestine of Lepidostoma hirtum and Crunoecia irrorata 

 (Lepidostomatidae) there were algae and plant detritus; the intestine of 

 Notidobia ciliaris (Sericostomatidae) was filled with leaves of moss 

 (this species inhabits moss-covered stones); remains of Copepoda and 

 insects were found only in the intestine of Sericostoma personatum, 

 although vegetable food was plentiful (Slack, 1936:107). The observations 

 on the larva of the American species Brachycentrus nigrosoma 

 made by Murphy (1919:155 — 158) showed that the freshly located larvae of 

 Br achy c ent ru s remains near the shore, in calm, small inlets among 

 stones; during the first five hours of their life they build the cases and feed 

 on diatoms (Cymbella, Navicula, Synedra); in the third week they 

 begin to add filamentous algae to the diet (Oedogonium, Cladophora, 

 Ulothrix) and higher plants; the larvae move to the water current after 

 6 weeks, where they attach the case to a stone so that their anterior end faces 

 64 the current. The larva then assumes a posture of waiting for prey in its 

 case (Figure 94): its head is inclined forward, the forelegs are extended 

 beyond the head; the long midlegs are held upward and the hind legs are 

 extended laterally. Animal food, consisting mainly of small Crustacea and 

 insects (mayflies, Tendipedidae), begins to predominate in the intestine of 



58 



