346 Pupa. Length of male pupa 2.0—2.3 mm, of female pupa 2.4— 2.7 mm; 

 antennae of male pupa reaching abdominal segment 7; antennae of female 

 pupa reaching abdominal segment 3. Head setae pale. Labrum with 

 indistinct, anterior angles and projecting anterior margin. Mandibles with 

 thin, long blades, which are finely serrated on the inner side. Wing sheaths 

 reaching beyond the end of the abdomen, in the male pupae slightly so, in 

 females distinctly. Postsegmental plates of segment 4 and presegmental 

 plates of segment 5 shown in Figure 446; number of spinules on the plates 

 of segmerts 3-7 as follows: 111:4-9+ 6-11; IV:3-7+ 7-13; V:3-8+ 8-12; 

 VI:4— 9; VII:4— 8; the increase in the number of spinules corresponds to 

 their decrease in size. 



The anterior (broad) end of the pupal case is convex; the ligaments are 

 short and situated at a distance from the angles of the case; the disks 

 consist of radially diverging filaments; posterior disks resembling the 

 anterior disks, but the ligaments are thinner (Figure 447). 



Mode of life and habitats. Stagnant water bodies and water 

 bodies with a slow current, in plant thickets. 



Distribution. European USSR, northwest, west, central belt and 

 southeast. In addition, Europe, Egypt. 



2. Oxyethira sagittifera Ris. 



Siltala, 1904b:24-29, 32-33, Figure 8, a-m; 1907:384-389, 393, 

 Figure 3, d. e. - Lestage, 1921:458-464. 



Full-grown larva. Length 2.7— 3.0 mm. Habitus as in Ox.costalis. 

 Head oblong, light yellow, slightly darker at the base of the mouthparts and 

 near the occipital foramen; dark spots present near the base of the middle, 

 frontal seta; seta 9 longer than width of head; There are two rows of small, 

 light spinules which form an angle in the median notch near the anterior 

 membranous margin of the labrum. Blades of left mandible with small, 

 blunt denticles; right mandible with a blunt apex and a large, subapical tooth 

 which is separated from the other part of the mandible by a notch; upper 

 blade of right mandible with 3 small teeth; lower blade with 2 or 3 small 

 teeth. 



Pronotum lighter than the other segments; its posterior margin, sides 

 and anterior angles blackish; posterior half of sclerite darker than anterior 

 half; Posterior margin, sides and anterior angles of meso- and metanotum, 

 blackish; dorsal setae of thorax as in Ox.costalis. Thoracic sternites 

 blackish brown, resembling those of Ox.costalis. 



Length ratio of legs 45:100:102; basal margin of coxae blackish. 

 Segments of midlegs and- hind legs darker in the basal part than in the 

 apical part; the forelegs appear therefore lighter than midlegs and hind 

 legs. A row of small, dark spinules on the outer side of the anterior 

 process of the fore tibiae (as in Ox.costalis); claws of midlegs and hind 

 legs with small light, dorsal spinules. Claws of the holding hooks with three 

 small dorsal denticles. 

 347 Pupa. Length 2.2— 3.3 mm. Antennae of male pupae reaching abdominal 

 segments 5—6, those of female pupae segment 2; antennae moniliform, 

 segments as broad as long or slightly broader than long. Labrum broad, with 



383 



