Mode of life and habitats. Small, stagnant water bodies thickly 

 overgrown with plants; also in water bodies with a slow current, among 

 vegetation. 



Distribution. Northern, western, central and southern regions of 

 the European USSR (var. danubicus Mart, occur in the southern region), 

 Siberia, Kamchatka. In addition, northern and Central Europe, Mongolia. 



2. Holocentropus stagnalis Albarda 



Siltala, 1905:128-129, Figure 33. 

 1921:501-502.- Lepneva, 1940:202. 



Ulmer, 1909:231,-297.- Lestage, 



Full-grown larva. Closely resembling larva of H. picicornis, 

 differing in pattern of frontoclypeus (Figure 650). Dark lateral stripes 



broad anteriorly; light median area near 

 anterior margin slightly dark; a transverse 

 row of distinct dark dots posteriorly; 

 posterior angle of sclerite also darker than 

 the other parts. The 3 teeth on lower blade 

 of right mandible of the same size, or middle 

 tooth smaller than the others. 



Pupa. Length 6.5— 8.0 mm. Anal lobes 

 longer and narrower than in H. picicor- 

 nis (Figure 65 1), rounded at the end, 

 diverging laterally; penis sheath slightly 

 longer and narrower than in H. picicor- 

 nis. Case made of loose tissue covered 

 with plant fragments, sand grains and silt. 



Mode of life and habitats. 

 Stagnant water, among plants and algae. 



Distribution. West of the European 

 USSR, the Caucasus, Western Siberia. In 

 addition, Europe. 



FIGURES 650 and 651. Holocentropus 

 stagnalis Alb. (after Siltala): 



650 — frontoclypeus; 651 — end of body of 

 pupa, ventral: male pupa (A), female pupa 

 (B). 



3. Holocentropus dubius Rambur 



Siltala, 1903:3-7, Figure 1.- Ulmer, 1909:230, 296. - Lestage, 1921 : 

 496-502, Figures 162, a, e, j; 164.- Lepneva, 1940:192, 205, Figure 145.- 

 Hickin, 1943:19-21, Figures 1-9. 



Full-grown larva. Length 12—14 mm (Figure 652). Frontoclypeus 

 slightly dark anteriorly, darker on the sides of the posterior part and near 

 the bifurcation of the frontal sutures; a curved row of brown dots anteriorly 

 on a dark background; sclerite lighter, lateral to this row; 2 large dots near 

 the middle frontal setae; a transverse row of dark dots in the posterior 

 449 part. Light spots on the sides of the sclerite, near the curvature of the 



frontal sutures; dorsal stripes extending from anterior margin to bifurcation 

 of frontal sutures; a light stripe lateral to the coronal suture; this stripe 

 with longitudinal rows of large dots; similar rows of dots present instead of 

 lateral stripes (Figure 653); sides with groups of dots ventroposteriorly. 

 Setae as in H. picicornis. 



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