3. Genus Cha e t opt e ry go p s i s Stein 



Mode of life and habitats. Small, running, clear water bodies, on 

 stones. 



Distribution. Northern part of the European USSR, Northern Urals. 

 Also Europe. 



1. Chaetopterygopsis maclachlani Stein 



Felber, 1908a:473-476, Figures 1-3; 1908b:248-253, Figures 1-5.- 

 Ulmer, 1909:267.- Dohler, 1914:50-51.- Lestage, 1921:802-809, Figure 290. 



Full-grown larva. Length 15— 18 mm. Head yellowish brown. Fronto- 

 clypeus with 3 dark dots on each side of median pit, 2 median dots further 

 posteriorly; wedge-shaped pattern formed by large dots (Figure 539). 



Short rows of large dots on site of dorsal stripes and lateral to coronal 

 suture; longitudinal, lateral rows of dots behind eye; groups of dots 

 ventrally near occipital foramen. 



Labrum yellowish, with deep median indentation; setae 5 and 6 dark and 

 relatively large. Mandibles short, black, each with 4 distinct teeth. 



Pronotum yellow (Figure 539); groove in anterior third with a narrow, 

 dark stripe in middle; dots of X- shaped pattern large, distinct; anterior- 

 angle and medioanal seta longer than others; anterior 

 margin with 4 short, or moderately long, strong setae. 

 Mesonotum (Figure 539) lighter and narrower than 

 pronotum, with large dots; posterior -angle margin 

 in form of a large, dark spot; posterior margin with 

 small, dark stripe in middle. 



Tergites of metathorax (Figure 539) slightly 

 sclerotized, yellowish, with thin setae; anterior- 

 median tergites relatively large, clearly separated. 



Legs light brownish; femora with distinct dots; 

 primary ventral setae of fore femur in form of strong, 

 yellow spines, posterior primary seta short, thin, 

 situated above basal spine. 



Dorsal and lateral processes of abdominal 

 segment 1 blunt, wide. Lateral line on segments 3—7 

 with small, thin hairs. Gills more strongly reduced 

 than in Chaetopteryx, absent from segment 6 

 onward dorsally, and sometimes also in ventral row; 

 pleural gills present only to posterior margin of 

 abdominal segment 3. 



Tergite of abdominal segment 9 brownish; medio- 

 anal setae long; anterior-angle seta markedly smaller; intermediate setae 

 long; both lateral setae short, thin; 2 setae between medioanal setae, one 

 moderately long, the other shore. Claw large, pointed, with a dorsal denticle. 



Case 20— 25 mm long, straight or slightly curved, slightly narrower 

 posteriorly, made of plant particles, especially leaves of moss (Fontinalis 

 antipyretic a). 



539 



FIGURE 539. Chaetop- 

 terygopsis maclach- 

 lani Stein. Head and 

 thorax, dorsal (after Felber, 

 with modifications) 



387 



