97 



secondary setae. Pronotum with comb of large, thick spines near anterior 

 margin. Horn present. Gills postsegmental on segments 2—4, presegmental 

 on segment 2, sometimes also on segment 3. Tergite of abdominal segment 

 9 always with 10 — 11 secondary setae, some of them well developed. 



Case made of coarse sand grains, rough in part or entirely, 11—21 mm 

 long, with irregular surface. 



Mode of life and habitats. On stones in the littoral. 



Distribution. USSR: Lake Baikal. Not known outside USSR. 



Key to Species 



Full-grown larva 



1 (2). Gula narrow, about twice as long as wide 



2. B. spinosa Mart. (p. 123) 



2 (l). Gula less long. 



3 (4). Presegmental gills present on abdominal segment 3 



1. B. bellicosa Mart. (p. 117) 



4 (3). Presegmental gills on abdominal segment 3 absent 



3. B.thamastoides Mart. (p. 127) 



1. Baicalina bellicosa Martynov 



Bebutova, 1941 : 92-94, Figures 18-31.- Lepneva, 1964 : 66 9-676, Figures 

 3, 7, 11, 13, 17. 



Full-grown larva. Length 10— 14 mm. Head chestnut brov/n (Figure 

 157, a) due to darker spinules on light brown background. In contrast to 

 the species described above, the spinules have the form of wide, conical 

 tubercles with slightly curved apex. Eyes large, on light background; 

 antennae light basally, with thick, dark sens ilia. Dots light, large, bright 

 in some places; tentorial pit dark. Frontoclypeus anteriorly with several 

 indistinct, lighter' transverse bands; posterior area with sharp wedge- 

 shaped pattern. Area before the eye near antenna and to anterior margin 

 dark; 4 large sharp dots lateral to posterior part of frontal sutures; 

 several similar dots further laterally and behind the eye. Groups of large, 

 conical, dark spinules lateral to gula (Figure 157, B). Anterior -margin 

 intermediate seta thick, moderately long, brown; median seta smaller, 

 yellowish; lateral seta short, thin, light; anterior frontal seta smaller, 

 middle frontal seta small, posterior frontal seta strong, long. Seta 7 short, 

 thin, situated anterior to the palp; seta 9 near anterior margin, moderately 

 long, reddish brown; seta 11 situated near posterior margin of eye, very thin, 

 small; seta 10 small, light; seta 12 short, thin, lateral to light periocular 

 area; seta 13 small; seta 14 long; seta 15 situated posteriorly nearby, 

 similar, both thicker than 9; seta 16 small, thin; seta 17 short, thin; 

 ventral seta 8 small, strong, dark brown; seta 18 slightly smaller, brown. 



Dorsal sclerite of labrum chestnut brown, with anterior processes 

 which almost reach the margin; membranous stripe at anterior margin 

 less broad than in the preceding species; posterior-angle sclerites large, 

 light brown at the end. Seta 1 blunt, small, situated anteriorly near end of 



117 



