detritus, except for a small posterior part and a few streaks of sand grains; 

 posterior end covered with a brown membrane v/ith a wide, round hole. 



Mode of life and habitats. Rapid mountain brooks and rivulets. 



Distribution. USSR: Middle Asia. 



2. Dinarthrum reductum Martynov, larva nova* 



Full-grown larva. Length 9— 10 mm. Head (Figure 611) grayish brown 

 dorsally, darker, rust brown laterally and posteriorly; frontoclypeus with a 

 transverse row of 4 large dots posteriorly; a small brown dot before the row; 

 360 epicranial suture flanked by distinct, light, small, rounded dots. Pronotum 

 (Figure 612) mainly grayish brown; darker, chestnut brown posteriorly in 

 middle, with large, light dots; one longitudinal and one oblique dot posteriorly 

 at median suture; posterior naargin black or blackish brown, sometimes 

 with 2 light dots in middle. 



eii 



612 



FIGURES 611 and 612. Dinarthrum red uc turn Mart. 

 611 — frontoclypeus; 612 — pronotum (A), mesonotum (B). 



Described from a larva from the Chirchika River, collected by L. Sibirtseva in 1954 (Sibirtseva, 1958:177). 



450 



