slightly curved, cylindrical or slightly narrower posteriorly; most cases 

 are made entirely or mainly of detritus; anterior end or entire anterior 

 part of case often consists of sand in full-grown larvae, posterior part of 

 detritus; in other cases, a narrow, anterior ring and entire ventral surface 

 consist of sand, but dorsal part is made of detritus; sand grains are firmly 

 cemented, pieces of detritus less smoothly, with some thin fragments, e. g., 

 conifer needles, projecting at posterior end; larva makes its case rarely 

 of fresh plant fragments, e. g., leaves ofHippuris vulgaris. 



Mode of life and habitats. In various types of running water, 

 often in small brooks and rivulets, close to bank, rarely in deep current 

 of large rivers, on open or slightly overgrown shores of lakes, on solid 

 bottom with abundant detritus, in a current or surf of moderate speed; the 

 larvae live on a stony, sandy- stony, sandy, or detritus -rich bottom in lakes 

 and running water, usually at a depth of 0.2— 1.0 m; they avoid silt bottom 

 and thick, vegetation in littoral zone. 



Distribution. Northwestern and northern parts of the European 

 USSR, including Northern Urals. In addition. Northern Europe, including 

 Finland, the Carpathians. 



2. Chaetopteryx villosa Fabricius 



Pictet, 1834:140-141, Plate VII, Figure 4.- Kolenati, 1848:72-72.- 

 Walser, 1864:61.- Wallengren, 1891:84.- Struck, 1899:325, Figure 24, a-d; 

 302 1900:15, Figure 22, a-d.- Ulmer, 1901:166-168, Figures 1-14. - Siltala, 

 1902:91-94, Figure 21.- Struck, 1903:100, Plate II, Figure 13.- Ulmer, 

 1903:70.- Siltala, 1904c:70; 1907:505.- Ulmer, 1909:265, 266-267, 

 Figure 399.- Dohler, 1914:49-51.- Lestage, 1921:796, 798-802, 

 Figures 285-289.- Hickin, 1948:59-61, Figures 1-10. 



Full-grown larva. Length 14— 16 mm. Head (Figure 529, A) brownish 

 or brown dorsally and laterally. Frontoclypeus darker, reddish brown 

 anteriorly laterally and at tentorial pit; 2 large, indistinct dots on each 

 side of median pit, 2 median pairs of dots, one pair behind the other further 

 posteriorly; wedge-shaped pattern on posterior part formed by large, 

 distinct, black dots. Dorsal stripes little differentiated, narrow, slightly 

 dark, brownish, absent in light specimens; a dark, reddish brown stripe 

 before eyes from base of antenna to anterior margin; large, sparse dots 

 situated on area of dorsal stripes lateral to posterior part of frontal 

 sutures and coronal suture; a short, transverse row of 3—4 large dots 

 medially to eye; sides of head with longitudinal rows of larger dots behind 

 eye; ventral surface dark brown, lighter at anterior margin; punctation near 

 occipital foramen on lighter background. Gula dark brown (Figure 529, B). 

 Setae black, arrangement and form as in C h. s a h 1 b e r g i. 



Dorsal sclerite of labrum reddish brown; posterior-angle sclerites 

 blackish at end; setae as in Figure 529. Mandibles black, spadelike, with 

 teeth at distal margin; lateral setae situated basally; dorsal seta short, 

 brown; ventral seta small, light (Figure 529, C). Maxillolabium as in 

 Ch. sahlbergi. 



Pronotum (Figure 530) yellowish brown; anterior margin narrow, reddish 

 brown; lateral margin brownish; groove in anterior third distinctly dark in 



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