and near the bifurcation of the frontal sutures; posterior stripe contiguous 

 laterally with the posterior margin of the median dark figure. Unlike in 

 A. ladogensis, light spot in posterior part of sclerite of A. palpata 

 smaller. Several small dots and a row of 5 or 6 coarser dots near the 

 posterior end of the median stripe; groups of 3 or 4 dots anterior to them 

 at the sides; a transverse row of 6 dots (3 dots on each side anteriorly); 

 a transverse process with a black dot and a brown, spinelike mediofrontal 

 seta in the middle, where the sclerite is narrow. 



Dorsal stripes at level of eyes sometimes interrupted or pale; dots on 

 stripes black or blackish brown, forming longitudinal rows along the coronal 

 suture; dots on sides of head also numerous, forming irregular longitudinal 

 rows on the light background; groups of small, light brown dots ventrally 

 near the occipital margin and 3 large dark dots on each side anterior to them. 

 Setae of head as in A. ladogensis but darker; seta 9, black; seta 7, dark 

 brown; setae 17 and 18, light brown, distinct. Covering setae, smaller and 

 sparser than in A. ladogensis, present in small numbers on the dark 

 figure. 



Dorsal sclerite of labrum (Figure 675) darker than in A. ladogensis; 

 pattern less distinct; posterolateral reddish brown spots smaller; median 

 spot near posterior margin little marked; covering setae very small, light; 

 secondary surface setae strong, reddish brown, less numerous than in 

 A. ladogensis; serration at end of yellow lateral hairs more distinct and 

 coarser. 



Teeth of mandibles (Figure 676) slightly blunt. Distally, left mandible 

 with 2 blunt, indistinct teeth and a small denticle between them; upper blade 

 with tooth; lower blade with 3 teeth and a basal tubercle; 6 yellowish 

 thicker and longer setae and a similar long, strong, dark brown seta among 

 the numerous light outer setae. Distal tooth of right mandible blunt; upper 

 blade with one tooth, lower blade with 3 teeth, basal tooth very small; middle 

 tooth larger than others; outer setae of varying length and thickness. 



Sclerites of maxillolabium reddish brown; submentum with slightly 

 concave anterior margin and convex lateral margin; 4 and 5 anterior-angle 

 setae longer than the others; cardo with 5 blackish brown setae at the inner 



475 angle near the base; 1 of these setae long; sclerites with thin, light setae 

 and several thick brown setae; stipes reddish brown; basal group of dark 

 setae, 2 of which are longer and thicker than the others; distal group with 

 1 such seta. 



Light mediolongitudinal stripe of nota of thorax absent; pattern of meso- 

 and metathorax distinct; lateral margins broadly black; median spots of 

 posterior margin as in A. 1 a d o g e n s i s; anterior margin darker in the 

 middle. 



Legs lighter and thinner than in A. ladogensis (Figure 677); secondary 

 setae of midlegs and hind legs less numerous. 



Abdomen similar, with a light pattern and with the same primary and 

 secondary setae as in A. ladogensis. Distribution of gills listed in 

 Table 12. 



476 Medioventral seta of segment 7 dark, situated near the posterior margin 

 on a small sclerotized dot; segment 8 without gills; ventral plates small, 

 thin, yellowish, fused in the middle; a narrow, reddish brown stripe with 



4 short, strong, black setae near the posterior margin. 



5724 540 



