1939] 
Immature Trichoptera 
17 
Labrum roughly rectangular, the anterior margin 
formed of 3 curves, in each of the two emarginations 
of which is a fine bristle; 5 longer bristles with 
curved tips vertically on either side of labrum ; spurs 
1-2-4 (Pharula) or 1-3-4 (Neothremma) : 
Sericostomatidae, subfamily Georinse in part 
12. Antennae very long, the outer part wound around the 
abdominal apex 13 
Antennae scarcely longer than body, the ends never 
wound as above 14 
13. Two mesotibial spurs; mouthparts so placed that the 
pupal mandibles point upwards : Leptoceridse 
Four mesotibial spurs ; mouthparts normal or as 
above: some Odontoceridse 
14. Spurs 2-2-2 (Micrasema) or 2-3-2 or 2-3-3 (Brachy- 
centrus) ; labrum obtusely triangular to semicir- 
cular; maxillary palpi shorter than or but little 
longer than labial palpi, never stouter : 
Sericostomatidae, subfamily Br achy centring 
Spurs not as above 15 
15. Case shaped like a snail shell, coiled in a flat spiral, 
made of sand grains of small size : 
Sericostomatidae, subfamily Helicopsychinae 
Case never of this form 16 
16. Less than four mesotibial spurs 17 
Four mesotibial spurs 18 
17. Body length not less than 5 mm. ; robust species : 
Sericostomatidae, subfamily Sericostomatinae 
Body length not over 4 mm.; slender, small species: .... 
Beraeidae 
18. Less than 4 metatibial spurs : some Odontoceridse 
Four metatibial spurs, the formula 2-4-4 19 
19. Anal processes lobate: 
Sericostomatidae, subfamily Lepidostomatinae 
Anal processes rod-like 20 
20. Case of sand, flattened dorso-ventrally and with lateral 
flanges, closed by discs of silk at the ends, that at the 
posterior end having a vertical slit, that at the ante- 
rior end a horizontal slit: Molannidae 
