Abdomen of more or less uniform width in segments 1 — 8; segment 9 

 small, very narrow, its dorsal side covered with a fold of the posterior 

 margin of segment 8. Abdomen with small setuliform covering setae as 

 membranous parts of the thorax. 



Dorsum of segments 1 and 2 with a narrow, yellowish brown, trans- 

 versely elliptical figure which is light in middle and surrounded by small 

 spinules with broad base and hooked, posteriorly directed apex; these 

 spinules form a broad stripe; this elliptical figure resembles the elliptical 

 postsegmental plates of segment 3 of the pupa of Hydropsyche; according 

 to arrangement of spines, these ellipses resemble presegmental pupal plates; 

 light middle of ellipse without spinules. 



Gills arranged in 4 rows, 2 in pleural region and 2 in ventral region; 

 ventral gills present on segments 1 — 8, pleural gills on segments 2—7 

 (Table 28); lateral, ventral gills with 2 branches, median gills with 1 branch; 

 arrangement of gills and number of filaments shown in Table 2 8. 



TABLE 28 



Segment 



Pleural 



Ventral 



subdorsal 



subventral 



lateral 



median 



Mesothorax 

 Metathorax 



1 



2 



3 



4 



5 



6 



7 



8 



14 

 16 

 17 

 16 

 12 

 10 



15+12 

 12+11 



12 



12 



12 



10 



19 



11 

 14+12 

 13+12 

 14+10 

 12+10 

 10+10 



8+8 

 13+10 



22 

 23 

 10 

 16 

 12 

 13 

 10 

 11 



Primary setae of abdomen thin, light, small, larger on posterior segments 

 than on anterior segments. Anterior-margin seta small, situated a distance 

 from anterior margin; anterior -angle seta larger than others, situated in 

 about the middle on segments 1 — 7, near anal setae on segment 8; medioanal 

 seta slightly shorter than anterior-angle seta; intermediate and lateral 

 setae small, distinct only on segment 8. 



Segment 9 small, narrow, its dorsal side covered by a fold of segment 8; 

 grayish yellow, thin, rhomboidal sclerites dorsally on the sides; they have 

 4 setae near posterior margin: 1 seta displaced laterally and posteriorly; 

 a brownish, long, anterior-angle seta and a similar, slightly smaller, 

 medioanal seta between them; a small, light, branched, intermediate seta 

 and a lateral branched seta, the former with 5 branches, the latter with 

 3 branches. Ventral side with thin, yellowish, triangular plates (Figure 755), 

 covered with short, conical spines anteriorly; spines long with a long fine 

 end in the middle; light setae with slightly thicker base near posterior and 

 537 lateral margin. Three brown setae on sides of sclerite; 5 anal gills. 



613 



