189 



Ends of case covered with plant fragments, small pieces of stalks, 

 rarely sand grains; anterior and posterior membrane with numerous holes. 



Mode of life and habitats. Detritophagous, limnophilous, in 

 littoral vegetation of lakes, ponds, swampy waters, and near coast of 

 freshened parts of the Gulf of Finland. Full-grown larvae and pupae occur 

 in late spring and early summer. 



Distribution. European USSR (western, northwestern, and central 

 regions). In addition, Europe. 



5. Limnophilus flavicornis Fabric ius 



Reaumur, 1737; Plate XII, Figures 6-10,- Degeer, 1778: Plate XI, 

 Figure 14.- Pictet, 1834:152, Plate IX, Figure 20, q-c. - Rambur, 1842:484.- 

 Kolenati, 1848:44-45.- Hagen, 1864:245-246.- Walser, 1864:58-60.- 

 Meyer, 1867:161. — Packard, 1870:617, Figure 609. - Preudhomme de Borre, 

 1870-1871 :67.- Wallengren, 1891 :48.- Rudow, 1897:454.- Lampert, 

 1897:154, Figure 69.- Struck, 1900:20, Figure 32.- Ulmer, 1900, Figure 4.- 

 Ostwald, 1901 :112.- Siltala, 1902:50-54, Figure 10, a-o. - Ulmer. 

 1902b:231-234, Figures 1-12.- Struck, 1903:81, Plate II, Figure 1.- 

 Ulmer, 1903:56-58, Figure E,49.- Siltala, 1 904c : 38-39. - Ulmer, 

 1909:259-260, Figure 390.- Lestage, 1921 :729, 733, 742, 744, 747, 

 Figure 255 b, 1, s.- Lepneva, 1940:215, Figures 159,4.- Hickin, 1943:6-10, 

 Figures 1-10. - Winkler, 1959 : 112-128, Figures 1-28. 



Full-grown larva. Length 19— 23 mm. Head (Figure 315, A) as in 

 L. rhombicus, dark, nearly black or blackish brown; pattern on 

 frontoclypeus reaching frontal sutures anteriorly; anterior area with 

 deep, lighter, yellowish brown, median, sometimes indistinct indentation; 

 2 large black dots, which are poorly visible in dark specimens, lateral to 

 indentation; longitudinal stripe wide, with large, light dots, usually reaching 

 frontal sutures posteriorly; posterior angle and middle of lateral areas 

 light. Dorsal stripes extending from anterior to posterior margin along 

 frontal sutures, darker anteriorly than posteriorly; punctation distinct 

 in posterior part. Lateral stripes wide, with longitudinal rows of dots, 

 space between stripes light, with a small, slightly dark area in middle. 

 Ventral surface mainly chestnut brown, with groups of darker dots on 

 each side posteriorly, with a light stripe near margin anteriorly; gula 

 light (Figure 315, B). 



Dorsal sclerite of labrum golden brown, median indentation deep, a small, 

 dark reddish brown spot behind median pit; posterior-angle sclerites short, 

 blackish brown. Seta 1 in form of a short, blunt, light spine; setae 2 and 4 

 forming small, light spines; seta 3 short, slightly longer and thinner; setae 

 5 and 6 larger than others, yellowish, thick, lateral to median pit, 5 larger 

 than 6. 



Mandibles black, oblong; left mandible with large median tooth, 2 

 smaller, wide teeth dorsal, and 2 narrow, sharp teeth ventral to median 

 tooth, ventral blade smooth, slightly concave, dorsal blade with a small, 

 rounded process distal to the brush; right mandible with 3 smaller teeth 

 dorsal to distal tooth, with one tooth ventrally. Lateral setae of mandibles 

 short, light, of about the same length, situated basally. 



236 



