Number and arrangement of gills of M . s i b i r i c a 



Segment 



Dorsal 



Ventral 



2 



1 





3 



1 





4 



1 





5 



1 





6 



1 





7 



1 





4. Genus Triaenode s McLachlan 



Full-grown larva. Length 8.5— 13 mm long, body almost uniformly wide, 

 slightly tapering posteriorly. Head slightly oblong, without white adfrontal 

 stripe; lateral stripes present; sensilla of antenna as in Mystacides, 

 long, with a short seta. Gula square, with a posterior median indentation. 

 Labrum with deep median indentation. Mandibles short, with large blunt 

 teeth. Submentum absent; maxillary palps short, middle segment slightly 

 longer than adjacent segments. 



Pronotum and mesonotum sclerotized, with distinct or pale pattern. 

 Metathorax much wider than mesothorax, with large lateral processes 

 directed anteriorly. Hind legs natatorial, with very long, divided tibiae and 

 undivided tarsi. Gills single. Tergite of segment 9 small, heart-shaped. 

 Claw of anal legs with 2 dorsal denticles. 



Case straight, narrower posteriorly, often much longer than larva, made 

 of spirally arranged, small plant particles. 



Pupa. Length 8.0— 11.0mm. Antennae of male pupae coiled 3—3.5 times 

 around body, Labrum with small, teat-shaped, median process; setae short. 

 Median margin of mandibles coarsely serrated, with a characteristic process 

 in middle. Wing sheaths reaching to segments 6—7. Fore and mid-tarsi 

 with natatorial setae. Holding apparatus on segments 3 — 6. Gills single. 

 Dorsal processes of segment 9 large, with 4 setae. Anal rods thin, long, with 

 shorter distal part, and with numerous, small setae on inner side. 



Mode of life and habitats. Stagnant and slowly running water, 

 often in vegetation, rarely on solid bottom. 



Distribution, The European USSR, including the Caucasus; Middle 

 Asia, Western and Eastern Siberia, Maritime Territory, the Amur Region, 

 In addition, cosmopolitan. 



600 



