dark brown; they are displaced posteriorly on segment 8 and form a row 

 with the surface setae. Anterior -margin setae of segment 1 small, light 

 yellow; they are even smaller and hardly marked on the following segments; 

 they are dark and more distinct on segments 7 and 8; Medioanal seta of 

 anterior and middle segments smaller, lighter and thinner than anterior - 

 angle seta; both setae similar and blackish brown on segments 7 and 8; 

 intermediate and lateral surface setae thin and small, almost transparent, 

 situated on small white spots lateral to the median seta; Ventral medioanal 

 seta of 1st segment small, light brown; that of segments 2 and 3 much 

 larger; it is very small and light on the following segments, especially on 

 segments 4 and 5; this seta is also dark brown on segment 8 and relatively 

 long, like the anterior -angle seta. 



Segment 9 laterally, with 3 strong reddish brown setae near the base of 

 the anal legs, one at the boundary with the dorsal part and 2 setae close 

 together at the boundary with the ventral part. 



Section "a" of anal legs (Figure 532) almost completely membranous 

 with a small, oblique, dorsal fold; a very narrow longitudinal rodlike brown 

 sclerite ventrally. Section "b" oblong, geniculate, with a wide brown latero- 

 dorsal sclerite; a row of indistinct dark dots near the dorsal margin; these 

 dots are more numerous in the basal part; the geniculate part of the 

 sclerite is forked, each prong of the fork very narrow, brown and with a 

 dark longitudinal stripe; the claw attached to the prongs; setae on the 

 sclerite as follows (Figure 532): 2 brown, moderately thick dorsodistal 

 setae above the prongs near the bend, which are the longest setae of the 

 sclerite; a thin yellow subapical dorsal seta of moderate length, which is 

 much shorter and thinner than the apical setae; 5 setae on the lateral 

 surface, which are similar to the distodorsal setae but shorter; subapical 

 part sometimes with an additional shorter seta among several other setae;* 

 a long ventral seta situated on a membrane near the margin of the sclerite, 

 slightly distal to the middle. Sclerites "c" form brown trapezoidal plates 

 and a small rounded plate with a short strong brown seta in the geniculate 

 part on the ventral side. 



Claws broad atthebase (Figure 532), dark, hook-shaped, pointed; 

 membranous transverse stripe of claw distinct; the dark brown, thick seta 1 

 situated at the boundary of the basal and apical parts on the dorsal side; 

 this seta is the longest seta of the claw; seta 2 situated lateral to this seta 

 on the outside; median seta 3 situated slightly more distally; both setae 

 thin, light brown, shorter than seta 1; the basal, relatively thick, reddish 

 brown seta 4 is situated on the median side of the claw near the membranous 

 stripe; the thin brown seta 6 is situated in the distal part on the outer side; 

 ventral seta 7 and 8 almost transparent, long, slightly curved; the small, thin, 

 dark, spinelike seta 5 is situated near seta 8 on the outer side. 



Young larva. Number of stages probably 5, as in Philopotamidae. 



First stage (?). Length 5 mm; head longer than pro- and mesothorax; 

 sutures on head and pronotum absent; periocular area white; other 

 parts of head and pronotum yellowish brown; dots indistinct; legs 

 light, pattern indistinct. Setae of head, especially setae of the fronto- 

 clypeus and seta 9 relatively long. Anterior -angle primary setae of pro- 

 387 notum also long; only 3 primary setae on the sclerite; lateral seta on the 



• The laterodistal setae are easily lost and possibly do not always develop completely; their full number 

 is rarely present in fixed material. 



433 



