Pupal case attached at anterior end; anterior and posterior openings 

 closed by a sievelike lid with large, irregularly distributed holes; both ends 

 covered above by pieces of plants or large sand grains and small stones. 



Mode of life and habitats. Running water, usually in parts with 

 a slow current; open shore of lakes, on a bottom with abundant detritus; 

 pupae occur in later- summer. 



Distribution. Western, central, and northern parts of the European 

 USSR, including Northern Urals. In addition, Northern and Central Europe. 



2. Halesus tesselatus Rambur 



Siltala, 1902:87-91, Figure 20.- Struck, 1903:61, Plate II, Figure 12.- 

 Ulmer, 1903:67-68; 1903b:202-204, Figures 33-38.- Siltala, 1907:504-505.- 

 Ulmer, 1909:269.- Dohler, 1914:50.- Lestage, 1921:785-795, 

 Figures 282-284.- Lepneva, 1928:79-80; 1904:216. 



Full-grown larva. Length 17—2 mm. Slightly darker than H. i nt e r - 

 punctatus. Head pattern similar, more distinct ventrally; spots near 

 tentorial pits darker. 



Pronotum with light brown posterior margin; posterior angle process 

 with blackish margin; black lateral anterior stripe of margin extending in a 

 narrow process before posterior median stripe almost to suture. Lateral 

 margin broadly black posteriorly. Most setae of thoracic tergites black. 



Mesonotum light brown anteriorly and in middle of posterior part, brown 

 in punctate area; posterior angle light, except area near lateral margin; 

 oblique streaks as in H. i nt e r pu n c t a t u s, pinkish; anterior margin with 

 black or dark brown stripe laterally; lateral margin with wide black 

 posterior half joining wide and black posterior angle margin; posterior 

 margin brownish in middle. 



Tergites of metathorax brown, distinct; anterior median tergites in form 

 of oblong triangles; posterior median tergites larger, irregularly triangular, 

 with whitish lateral area; lateral tergites large, with a transverse band 

 composed of a large reddish brown dot, longitudinal lines, and a small dot. 

 286 Prosternite (Figure 505) yellowish, not dark posteriorly or with a narrow 

 stripe, with dense group of 16—18 small, pinkish, dots laterally. Mesothorax 

 ventrally with a row of pinkish dots. Ventral side of metathorax with pale 

 dots. 



Legs (Figure 506, A— C) brown. Primary ventral setae of fore femur in 

 form of 2 light yellow, large pointed spines, apical spine longer than basal; 

 posterior seta dark, thin, as long as subapical seta of trochanter, situated 

 above basal spine or slightly more basally, rarely apically. Primary 

 ventral setae of mid- and hind legs as in H. inter punctatus. 



Lateral line from end of segment 3 to beginning of segment 8, formed by 

 small, dark, hairlike spinules. Gills on segments 2—7. 



Tergite of segment 9 light brown, with indistinct punctation at anterior 

 margin; medioanal seta black, long, sometimes situated near a smaller 

 seta; anterior-angle seta similar, thick, dark, slightly smaller; inter- 

 mediate seta thin, moderately long, brown; lateral setae, a primary and a 

 secondary, short, thin; tergite with isolated, small, surface setae. 



358 



