ventral seta. Form and chaetotaxy of legs similar in the 2 species. 

 Ratio of length of legs = 56:100:94. 



Lateral line from middle of segment 3 to end of segment 8; hairs small, 

 brownish; a number of pinkish sclerotized dots above hairs in anterior half 

 of segments 111:6-8; lV:8-9; V: 4-8; VI:14-6; VIl:4-4; VlII:4-5. 



Gills on segments 2—8. 



Number and arrangement of gills ofN.admorsus 





Segment 



Dorsal 



Pleural 



Ventral 



2 



3 

 3 



3 



3 



3 

 3 



3 



3 

 3 



3 



3 



3 

 3 



4 



3 

 3 



3 



2 



3 

 3 



5 



3 

 3 



2 



2 



3 

 3 



6 



2 

 2 



2 



2 



3 

 3 



7 



2 

 2 



1 



1 



2 

 2 



8 



2 









2 



Tergite of segment 9 pale, whitish, often with fine, pinkish punctation at 

 anterior margin. Medioanal seta and anterior -angle seta long, black; 

 intermediate and lateral seta short, brownish; usually no setae between 

 medioanal setae. 



Sclerite "b" of anal legs light brown, with pinkish dots; median and 

 neighboring seta dorsally at distal margin long, black, thick; 3rd apical 

 dorsal seta and median subapical seta shorter and thinner; ventrodistal 

 seta black, moderately long; 2 similar surface setae; there are also 

 2 thin, short setae at median margin and in punctate area, and 2—3 small 

 setae (surface setae of N. punctatolineatus more numerous but 

 smaller). Sclerite "c" reddish brown, with broad, reddish black margin; 

 seta small, thin. Claw reddish brown, with 2 dorsal denticles, brownish 

 black at the apex; setae as in N. punctatolineatus. 



Case (Figure 257, A) 36—40 mm long, made of small fragments of tree 

 detritus, usually flat, thin pieces, like leaves, arranged obliquely or in a 

 longitudinal pattern; surface fairly or perfectly smooth; ends open 

 (Figure 257, b). The case of young larvae (Figure 257, C) of stages 1—3 

 (larval length 10— 11 mm, length of case 15— 16 mm) is made, as in 

 N. punctatolineatus, in form of a tube with an upper and lower layer 

 of green leaf fragments, overlapping transversely so that fragments project 

 laterally; this seems to be typical for the genus. Full-grown larvae of 

 N.admorsus live in slow-running water; transition to a more rapidly 



190 



