5 (2). Basal seta of claw of mid- and hind legs with blunt, apparently 



broken apex; case made of small, densely arranged plant fragments, 



with convex, rooflike dorsal side and flat ventral side 



6, Oecetis sp, 2 (p. 647) 



6 (1). Basal seta of claw of mid- and hind legs rudimentary, in form of a 



small tubercle, sometimes absent; case made of mineral particles, 



7 (8). Head pattern pale, larvae in brackish water 



2. O. intima McL. (p. 632) 



8 (7). Head pattern distinct, larvae in fresh water. 



9 (10). Prothorax with several thin secondary setae on lobe of trochantin, 



in addition to the primary seta; posterior margin of segment 9 only 



with primary setae 3. O. lacustris Pict. (p. 634) 



10 (9). Prothorax with one primary seta on lobe of trochantin; posterior 

 margin of segment 9 with several secondary setae in addition to 

 primary setae 1. O. ochracea Curt. (p. 625) 



Pupa 



1 (4). Case made of plant fragments; mandibles curved at end, very thin, 



with slightly concave lateral part basally, blades with large basal 

 denticles. 



2 (3). Case made of small, transversely arranged particles, posterior part 



tapering, anterior part sometimes tapering, surface not smooth 

 4. O.furva Ramb. (p. 637) 



3 (2). Case straight, cylindrical, with regular rows of rectangular, 



obliquely arranged particles 



5. Oecetis sp. 1 (Lake Kurgal'dzhin) (p. 643) 



4 (1). Case made of sand grains; mandibles regularly curved, less 



tapering distally, their basal part with straight lateral margin; 

 basal denticles of blade slightly larger than apical denticles. 

 500 5 (6). Anterior margin of labrum with large, long median process; fore 



and mid tibiae with numerous setae; number of spurs 1, 2, 2; dorsal 



processes of segment 9 with 9 — 12 setae 



1. O. ochracea Curt. (p. 625) 



6 (5). Anterior margin of labrum with short median process; fore and 

 mid tibiae with few setae; number of spurs 0, 2, 2; dorsal 



processes of segment 9 with 3 — 4 setae 



3. O. lacustris Pict. (p. 634) 



1. Oecetis ochracea Curtis 



Klapilek, 1893:99— 103, Figure 27.— Ulmer, 1903:109—110.— Siltala, 1905: 

 81— 84, Figure 21; 1907:480—482.— Ulmer, 1909:246— 247, 308, Figure 452a.— 

 Lestage, 1921 :639— 647, Figure 221b, c, f, j, n, o. — Lepneva, 1940:193,210, 

 Figure 147b. 



Full-grown larva. Length 13— 14mm. Head (Figure 799, A) slightly 

 oblong, pale yellow, with distinct pattern of dots; eyes small, situated some 

 distance from the anterior margin; antennae situated at margin; sensilla thin, 

 light, much smaller than in preceding species, with a small seta. Frontoclypeus 



625 



