with 9—11 denticles. Posterior end of male pupae blunt; penis broad at the 

 end and two small ventral lobes below it. 



Pupal case 3.0—4.1 mm long, grayish or light yellow, transparent; sides 

 of the case almost parallel posteriorly; anterior margin slightly convex, 

 almost straight; posterior membrane situated inside the neck, not visible 

 outside; each angle of the anterior margin with one disk; disks with stalks 

 thin; 2 posterior disks with short stalks, which are sometimes replaced by 

 one large median disk without a stalk. 



Mode of life and habitats. Mainly in plant thickets. 



Distribution. Northwest of the European USSR. In addition, 

 Northern Europe. 



5. Oxyethira frici Klapalek 



Siltala, 1904b:29-30, Figure 9, a-g. - Ulmer, 1909:226, 293, Figure 428, b. - 

 Lestage, 1921:458-464. 



Full-grown larva. Length 2.8— 3.0 mm. Larvae darker than those of 

 other species; sclerotized parts brown; pattern dark. Head dark brown, 

 without pattern; frontoclypeus without dark spots, with light spots in some 

 places. Upper blade of left mandible with 2 large projecting teeth and a 

 small tooth between them; lower blade with several small teeth. 



Pronotum slightly lighter near the anterior margin than the other 

 uniformly brown area; there are indistinct light spots in some places; 

 349 lateral and posterior margin with a narrow blackish brown border; anterior 

 half of meso- and metathorax (especially anteriorly) dark brown, darker than 

 the ground color; anterior and posterior angles and lateral part of posterior 

 margin black. Thin, light, sparse hairs on the outside of the process of the 

 fore tibia. 



Pupa. Length 2.1— 2.7 mm. Antennae of male pupae reaching the 

 7th abdominal segment. Presegmental plates of abdomen oblong, with large 

 spines in longitudinal rows. Posterior end of male pupae rounded dorsally; 

 penis blunt, broadened at the end; end of body without two ventral small lobes 

 covered with spinules. Length of pupal case 3.0—4.1 mm, width of neck 

 0.4—0.5 mm, width of posterior end 1.1 — 1.2 mm; broad margin of case 

 strongly convex, narrow, with a laterally projecting membrane. Angles of the 

 broad raised anterior margin with two attachment disks with separate stalks, 

 which originate in one point; sides of narrow part of case with two disks, 

 which are sometimes replaced by one large median disk or by 3-5-6 disks; 

 these disks are rarely without stalks. Case yellowish brown; old cases 

 left by the pupae are dark brown, sometimes blackish. 



Mode of life and habitats. Running water, on the bottom; pupae 

 on stones. 



Distribution. European USSR, northwest and central belt. In 

 addition, northern and Central Europe. 



6. Oxyethira tristella Klapalek 



Klapalek, 1897:11-16, Figures 5-6.- Ulmer, 1903:133.- Lestage, 

 1921:463-464. 



386 



