Wing sheaths reaching end of abdominal segment 5. Natatorial setae 

 present on fore and mid-tarsi. Presegmental plates present on segments 2 

 and 8, small, with 5 or 6 straight spinules; postsegmental plates curved, 

 situated near the posterior margin of segment 5, with numerous spinules. 

 Gills present on segments 2—7. Anal lobes rounded, with numerous setae. 



Walls of case loose, with a covering of sand grains or detritus, pupa lying 

 in a cocoon of gray loose tissue. 



Mode of life and habitats. Larvae predacious, free-living, 

 building capturing nets; they occur in running water and on lakeshores. 



Distribution. European USSR, the Caucasus, Western and Southern 

 Siberia, Middle Asia. In addition, Europe, Africa, northwest China, Iran, 

 North America, South America (Argentina). 



1. Polycentropus flavomaculatus Pictet 



Pictet, 1834:220-221, Plate XIX, Figure 2.-Klapalek, 1888:54-56, 

 Figure 19.- Struck, 1903:119, Plate IV, Figure2.- Ulmer, 1903:119, Figure 70,- 

 Siltala, 1903c: 12, Figure 4; 1905:124-125; 1907:404-406, Figure 6, d. - 

 Ulmer, 1909:230, 297, Figure355, b.- Lestage, 1921:491-494, Figure 159.- 

 Lepneva, 1940:201, 205, Figure 152, 4. 



Full-grown larva. Length 12—13 mm. Head oblong-elliptical, dorso- 

 ventrally compressed (Figure 63 1). Eyes large, consisting of 6 facets 

 433 arranged in a ring at about a fifth of the head from the anterior margin. 

 Head light yellow. Frontoclypeus slightly dark anteriorly; sides of 

 anterior part with narrow grayish brown stripes close to the margin; in 

 dark specimens, the stripes on both sides are broader posteriorly and 

 almost converge, forming a small dark band near the curvature of the frontal 

 sutures; this band is little marked in light specimens. Anterior and 

 curved rows of dark dots, which form an elliptical punctate figure, anterior 

 and posterior to the band; anterior arc with 6 dots; posterior arc with 

 6 or 7 dots, which are larger in the middle; a small lateral dot on the 

 posterior end of the dark lateral stripe. Posterior angle without pattern 

 posterior to the punctate figure; it forms a light heart-shaped spot on the 

 dorsal surface. Lateral anterior-margin seta in the anterior angle light, 

 curved; intermediate seta straight, dark, long, situated at a marked distance 

 from the lateral seta, near a small thin median seta (Figures 621, 623); 

 antero- and middle frontal setae short, thin, situated behind each other in 

 the anterior part; posterofrontal seta is one of the longest setae of the 

 head, dark, situated near the suture, on the light, heart-shaped figure. 



Dorsal stripes close to the margin, beginning from the clypangulus, 

 extending to the middle of the coronal suture, where the stripes of both 

 sides are connected; stripes narrow anteriorly; they are interrupted near 

 the curvature of the frontal sutures, broad posteriorly, with large and small 

 dots; 2 dots along the frontal suture one behind the other; 2 smaller dots 

 near the coronal suture; groups of small dots posterior to the stripes near 

 the occipital foramen; lateral stripes replaced by longitudinal rows of dots. 

 Seta 9 straight, longer than the others; seta 11 thin and dark, slightly longer 

 than the anterofrontal seta situated near seta 9; dark seta 7 situated near 

 the anterior margin, shorter than seta 9; the short light, slightly curved 

 seta 10 situated lateral to the eye; small seta 13 and the long brownish black 

 seta 12, which is the thickest seta of the head, posterior to the eye; setae 14 



489 



