Wing sheaths reaching abdominal segments 4—5; midlegs natatorial; 

 segments 1—3 of fore tarsi, especially in female, usually with sparse, thin 

 setae like the segments 1—3 or 1—4 of hind tarsi. 



Process of abdominal segment 1 with small spinules on saddle -shaped 

 process. Holding apparatus on abdominal segments 3—7; number of 

 spinules: 111:2-3; IV:2-3; V:2-5 + 8-12; Vl:2-4; VII:2-4. 



Gills on abdominal segments 2—7. 



Anal rods 1.0—1.1 mm long, thin; all 4 setae dark, strong, first seta 

 situated in basal half, 2nd seta at beginning of distal half, 3rd and 4th 

 setae larger, situated apically and subapically. Sheath of ventral appendages 

 and penis sheath of same length, the latter with large lobes (Figure 376). 



Case as in larva; sand grains sometimes larger, forming a less smooth 

 surface; ends of case rounded covered with sand grains, anterior and 

 posterior membranes situated inside case, with numerous fine holes. 

 Case attached to stones or other solid substrate. 



Mode of life and habitats. Littoral of lakes, open or slightly 

 overgrown, on solid bottom; brooks and rivulets with a moderately rapid 

 current. 



Distribution. Northwestern, western, central, and southern parts 

 of the European USSR, including the Crimea and Caucasus. In addition. 

 Central and Northern Europe, Iran, Japan. 



Number and arrangement of gills of pupa of L.a f f i ni s 

 Cafter Siltala) 



Segment 



Dorsal 



Pleural 



Pleural 



Ventral 



2 



3 

 3 



2 



3 



3 



3 



3 



3 

 3 



3-2 



2-1 



3 

 3 



4 



3 

 2 



2-1 



1 



3 

 3-2 



5 



2-1 

 2 



1(0) 



1(0) 



2 

 2 



6 



2 

 2-1 







2 



7 



2-1 







2-1 

 2-1 



15. Limnophilus centralis Curtis 



Pictet, 1834:156, Plate X, Figure 2.- Hagen, 1864:250.- Walser, 1864: 

 70.- Meyer-Diir, 1875, 388.- Rudow, 1897:452.- Siltala, 1902:62-65, 

 Figure 13.- Ulmer, 1903:54.- Siltala, 1904c:49.- Ulmer, 1909:264.- 

 Dohler, 1914:32.- Lestage, 1921 : 738-739, 746.- Lepneva, 1940:215, 223.- 

 Hickin, 1954:96-98, Figures 1-6. 



Full-grown larva. Length 10.5— 12.5 mm. Frontoclypeus (Figure 377, A) 

 uniformly brown; posterior angle sometimes lighter; anterior part with 



270 



