(485; 



487 



777 



Full-grown larva. Length 10— 12 nam. 

 Yellow ground color of head (Figure 779, B) 

 visible near eye and posteriorly; other 

 parts of head brownish, slightly darker 

 dorsally; pattern indistinct, except in some 

 parts posteriorly only, where it is distinct. 

 Frontoclypeus without pattern anteriorly or 

 sides slightly darker and with indistinct 

 dots; posterior part with 2 median dots situated 

 one behind the other, instead of in a 

 transverse row; lateral dots absent or in- 

 distinct. Dorsal stripes rarely slightly 

 visible, with indistinct dots; a row of 4 large 

 dots along coronal suture, 2—3 dots further 

 laterally; lateral stripes replaced posteriorly 

 by longitudinal rows of large dots; ventral 

 surface with large, indistinct dots 

 (Figure 779, C). Gula slightly dark, tapering 

 posteriorly. Setae as in T. bicolor.='= 



Main color of thoracic sclerites yellow; 

 pattern pale (Figure 780). Pronotum with 

 2 dark streaks near median suture, each 

 streak with 2 dots, which are sometimes 

 indistinct; posterior part laterally with 

 groups of pale dots on a brownish background. 

 Mesonotum brownish in middle, 1—2 large 

 dots on each side of anterior margin, and 

 a transverse row of 3 — 4 pale dots lateral 

 to suture. 



Case (Figure 779, A), as in T . b i c o 1 o r , 

 made of spirally arranged, small, oblong, 

 plant particles, case sometimes 15 mm 

 long tapering posteriorly. 



F*upa. Length 9 — 10 mm. Labrum 

 (Figure 781, A) wide, short, with distinct 

 teat- shaped median process. Mandibles 

 with strongly concave, coarsely serrate 

 blade (Figure 781, B), Sheaths of fore wings 

 reaching to segment 6. Lateral process of 

 1st abdominal segment as in Figure 781, C. 

 Holding apparatus on segments 3—6. Anal 



rods (Figure 781, D) straight, thin, tapering posteriorly, with strong 



spine-shaped seta between basal and apical part; median side with thin, 



hairlike setae. 



Case as in T. bicolor. 



Mode of life and habitats. Slowly running waters, calm areas 



among vegetation. 



Distribution. Central and western parts of the European USSR. 



In addition, Europe. 



77^ 



FIGURES 777 and 778. 

 bicolor Curt. : 



Tr ia eno d es 



777 - larval case fA) and detail (B); 



778 — pupa: left mandible, ventral (A), 

 anal rods (B) (778, B - after Klapilel<). 



Only part of the setae are shown in the drawing (after Hickin, 1954, Figure 3). 



608 



