Larval case 16—19 mm long, straight or slightly curved, made of plant 

 particles, fragments of plants or decayed leaves of more or less uniform 

 size and form but contrasting color; light yellow fragments alternating 

 with dark brown fragments; case surface smooth, particles firmly cemented; 

 anterior opening with projecting dorsal margin, posterior end rounded, 

 narrow, closed at margins by plant fragments, but leaving a round or 

 irregular opening in middle (Figure 521). 



Pupa. Length of male pupae 16— 17 mm, of female 17— 18 mm. Antennae 

 reaching beginning of abdominal segment 8. Labrum and mandibles as in 

 M. nycterobia. Wing sheaths rounded posteriorly, reaching end of 

 abdominal segment 4. Midlegs natatorial; hind legs with sparse setae on the 

 4 proximal segments. 



Dorsal process of abdominal segment 1 with deep, saddle- shaped 

 indentation. Holding apparatus on segments 3—7, number of hooks: 111:3—4; 

 IV:7— 8; V:7— 9 + 14— 23; VI:7-11; VI1:7-11. Gills on segments 2-7 

 (see p. 372). 



Anal rods 0.6 mm long, straight, with numerous spinules at end, slightly 

 curved; 1st seta situated in basal third; 2nd seta about the middle, 3rd and 

 4th setae subapically and apically. 



Ventral appendages of male genitalia wide, long; penis sheath much 

 shorter, bifid. 



Pupal case 16— 20 mm long, made of densely arranged plant pieces of 

 about the same size; sand grains often present at posterior end; anterior 

 and posterior sievelike membranes thin, with numerous small holes, 

 membranes covered with plant fragments, larger ones at anterior end; 

 small sand grains sometimes present among detritus. Pupal cases are 

 often covered with a thin layer of silt, which imparts to them a reddish brown 

 color. 



Mode of life and habitats. Brooks with slow current, including 

 cold, spring-fed brooks; pupae appear in late spring and early summer. 



Distribution. Northern (Solovetskie Islands), northwestern, and 

 central parts of the European USSR. In addition. Northern (Finland), Central 

 and Western Europe (Britain). 



3. Micropterna sequax McLachlan 



Pictet, 1834:132, Plate VI, Figure 1.- Struck, 1900:14, Figure 21; 

 1903:95-99, Plate II, Figure 11; Plate VI, Figure 19, a, b. - Ulmer, 1903: 

 66-67; 1909:268.- Lestage, 1921:782-785, Figure 280.- Hickin, 1953: 

 163-165. 



Full-grown larva. Length 18— 19 mm. Frontoclypeus (Figure 522, A) 

 brown anteriorly, punctation not always distinct, yellowish or yellowish 

 296 brown posteriorly, with distinct wedge-shaped pattern of large dots. Head 

 brown anteriorly lateral to frontal sutures, with a dark brown stripe before 

 eye, yellowish brown posteriorly; a narrow, brownish stripe reaching frontal 

 sutures and with transverse punctate rows lateral to them on area of dorsal 

 stripes; large dots along coronal suture; sides of head with longitudinal 

 rows of dots. Ventral surface brown, yellowish brown in some places 

 (Figure 522, B). 



371 



