spinules. Setae concentrated in the basal part; setae 1 and 5 situated 

 dorsally near the base of the claw; setae 2 and 3 situated closer to the 

 transverse stripe; seta 6 situated laterally near the membranous transverse 



stripe; setae 3 and 6 brown and relatively 

 long, thick; seta 2 short and thin; seta 8 

 (440) <£§§?& W spinelike, light, relatively large, situated 



near the basal margin of the membranous 

 transverse stripe; small, thin seta 4 

 situated near the basal margin; seta 7 

 absent. 



Young larva. The number of stages 

 of P. flavomaculatus is not exactly 

 known; there are probably 5 stages. 

 Siltala (1906:404-406,408) observed 

 4 molts of P. flavomaculatus in an 

 aquarium; Siltala adds a 6th stage, 

 "full-grown larva," which he described 

 from larvae collected in nature; he 

 gives the following differences from the 

 5th stage: dark spots at the base of the 

 large setae of the me so- and metathorax* 

 and a difference in the number of 

 secondary setae. As it is difficult to 

 count the small setae, and as there are 

 probably variations in the number of 

 secondary setae (especially in an 

 aquarium), we cannot consider proven 

 the existence of a 6th larval stage. We 

 give here only some remarks on the 

 first 4 stages, which were described 

 briefly by Siltala (1907:404-406). 



First stage. Length 1.8— 3 mm. Head 

 broad, higher than body at beginning of 

 stage; this difference disappears at the 

 end of the stage; epicranial suture 

 439 marked only in the basal part, including the bifurcation of the frontal sutures. 

 Sclerites light yellow; pattern absent; setae relatively long. Thoracic 

 segments equally broad; pronotum without posterior -angle processes. Ratio 

 of length of tibia, tarsus and claw of all 3 legs 100:100:127, 86:100:119, 

 86:100:119. Claws thin, slightly curved; ventral seta situated in about the 

 middle of the claw; a row of microscopic spinules basal to the seta; spinule 

 at base of seta larger than the others, as in the 2nd stage (Figure 631). 

 Section "a" of anal legs shorter than section "b." 



Second stage. Length 2.4— 4.3 mm. Head with indistinct stripes and dots. 

 Processes of hind angles of pronotum present; ratio of length of tibia, 

 tarsus and claw of 3 legs 125:100:140, 116:100:140, 107:100:129; seta of 

 claw situated further basally than in 1st stage. Dorsum of thoracic and 

 abdominal segments with an indistinct pattern of light lines. 



Third stage. Length 4.5— 6 mm. Dorsal pattern of head almost as in 

 the full-grown larva, indistinct ventrally. Ratio of length of tibia, tarsus and 

 claw of the 3 legs 150:100:150, 130:100:130, 126:100:117. 



* I did not find these spots in the full-grown larvae of P. flavomaculatus at my disposal. 



FIGURES 634-636. Polycentropus fla- 

 vomaculatus Pict.: 



634— pupa in its case, ventral; 635 — labrum 

 of pupa; 636 — right mandible of pupa, dorsal 

 (A); part of blade near distal part (B). 



497 



