behind it; setae 12 and 14 and several small secondary setae are situated 

 posterior to the eye; setae 16 and 17 light; seta 17 situated near the eye. 

 Ventral seta 18 small, little marked. 



466, 



FIGURES 666 and 667. A rctopsyche ladogensis Kol.: 



666 - head, dorsal (A) and ventral (B) (secondary setae shown only partly; covering setae 

 not shown); 667 — labrum, dorsal (A), pectinate hairs of anterior- angle tuft (B). 



Anteclypeus pale, relatively short. Labrum (Figure 667) short and broad; 

 ratio of length to width 1:2.3. Anterior margin of labrum narrowly 

 membranous; median indentation of dorsal sclerite replaced by a small 

 tubercle covered with short dark hairs; sides of anteclypeus near the 

 membranous margin with a dense tuft of golden brown hairs which are 

 flattened, and finely serrate at the end (Figure 667, B). Dorsal sclerite pale 

 yellow, brownish at the sides in the anterior third with a broad brown longi- 

 tudinal indistinct median stripe in the middle; posterior angles and 

 posterior-angle sclerites dark brown. Anterior part of labrum and area 

 lateral to the dark median stripe with numerous dark brown and brown 

 setae, 2 of which are longer (primary setae 5 and 6). 



Mandibles massive, dark brown and long. Left mandible with 2 large 

 apical teeth; upper blade with a small tooth; lower blade with 4 teeth, the 

 basal tooth indistinct; median brush consisting of short light chetoids; 

 a small brush of small light hairs near the basal tooth. Outer surface of 

 mandibles with light yellow setae of varying length; 16 or 17 such setae on 



531 



