Wing sheaths reaching abdominal segment 4. Mid-tarsi with poorly 

 developed natatorial setae; hind tarsi with sparse setae. 



Gills on abdominal segments 2 — 8, as in larva. Holding apparatus 

 with following number of hooks : 111:1-4; lV:2-3; V:2-3+10-ll; 

 VI: 2— 3; VII: 3. First seta of anal rods situated in basal quarter, 2nd 

 about middle or more distally; 3rd and 4th setae situated apically and 

 subapically (Figure 400 ). 



Penis sheath very large, wide, with deep median indentation and 2 large, 

 round lobes; ventral appendages with shorter sheaths. 



Case straight, as in larva; anterior and posterior end attached among 

 moss. 



Mode of life and habitats. Swamps. 



Distribution. Northwestern, western, and central parts of the 

 European USSR, Caucasus. In addition, Europe. 



21. Limnophilus sericeus Say (Limnophilus 

 despectus Walker) 



Siltala, 1902:68-71, Figure 15; 1 903a:23. - Ulmer, 1 903 : 54; 1909:262. 

 Lestage, 1921:736, 746. 



F^ill-grown larva. Length 11— 13 mm. Head dark brown but less dark 

 than foregoing described species, with light, yellowish spots in angle of 



frontoclypeus and near tentorial pits; 

 punctation bright. Ventral surface 

 brown, light near occipital margin, with 

 groups of dark dots. 



Pronotum chestnut brown; middle of 

 groove in anterior third and posterior 

 submarginal area darker than other 

 surface; posterior margin with 2 wide, 

 transverse stripes. Mesonotum less 

 dark, with narrow, black, posterior 

 margin. 



Legs brown, with indistinct punctation. 

 Lateral line on segments 3—7. Gills 

 on segments 2 — 8. Tergite of abdominal 

 segment 9 pale, indistinct, with 8—9 

 secondary setae situated between 

 medioanal setae and on surface, in addition to primary setae. 



Claw of anal legs with a large dorsal denticle, several, small, light 

 spinules near it. 



Larval case (Figure 40l) 14— 17mm long, straight, slightly narrower 

 posteriorly, smooth, made of small and large plant fragments arranged 

 longitudinally. 



Pupa. Length 10—12 mm. Antennae reaching middle of segment 8 or 

 slightly longer. Mandibles with relatively wide distal part; median blade 

 almost straight, dorsal lateral seta slightly longer than ventral. 



^01 



FIGURES 401-403. Limnophilus seri 

 ceus Say (after Siltala): 



401 —larval case; 402 - left anal rod of 

 pupa; 403 — penis sheath and ventral 



appendages of pupa. 



285 



