205 SYSTEMATIC PART 

 ORDER TRICHOPTERA 



Full-grown larva. Length 2.5—40—45 mm. Body elongate, divided into 

 head, thorax and abdomen, slightly dorsoventrally flattened or cylindrical. 

 Head prognathous or hypognathous; antennae rudimentary; eyes small. 

 Mouthparts well developed: mandibles of biting or cutting type; 

 opening of spinning glands at the end of the labium. Pronotum, and some- 

 times also meso- and metanotum, completely sclerotized or meso- and 

 metanotum membranous or partly sclerotized. 



Legs of walking type; forelegs of many species raptorial; hind legs 

 sometimes natatorial. 



Abdomen with 9 segments, boundaries between them always well marked; 

 constrictions sometimes deep; 1st segment shorter than the others, with a 

 dorsal and lateral tubercle in some forms; segment 9 with 2 anal legs with 

 claws. Tracheal gills present on abdomen, rarely on thorax and abdomen; 

 some families have no gills. 



The larvae build tunnel- shaped tubes, capturing nets or portable cases 

 of various forms with a covering of plant or mineral particles. 



Pupa free. Head with large, faceted eyes and long antennae, which are 

 sometimes curled around the body's posterior end. Labrum flat, with 

 thick, vertical setae; mandibles thick, cutting, with teeth or serrated on the 

 inner side; maxillary and labial palps resembling those of the adult. 



Mesothorax is the largest thoracic segment, prothorax the smallest; 

 the wing sheaths envelop the body laterally and ventrally. 



Legs long; tarsus 5 -segmented, as in the adult; the terminal (6th) 

 segment bears 2 small, weakly sclerotized terminal claws; midlegs 

 natatorial, with dense setae on the tarsi. 



Abdomen spindle-shaped, longer and thicker than in adult; dorsum of 

 segments 3—6 or 3—8 with small sclerites covered with spinules. 



The anal appendages form rods or lobes with thick setae in most forms. 

 Ventral processes contain the developing genitalia. 



Pupae situated in cavelike, shield-shaped cases or in cases resembling 

 larval cases which are sac -shaped or tubular; pupal cases are attached to 

 the bottom or rarely lie free on the bottom. 



Mode of life and habitats. Benthic organisms; living on the bottom 

 rarely on algae; larvae microphagous, algophagous, phytophagous, detrito- 

 phagous and rarely predaceous. They live in fresh, running or stagnant 

 water, some forms in brackish water. 



Distribution. Cosmopolitan. 



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