shells; their cases are usually flattened, and they are therefore called 

 sacciform; their form varies; they may be elliptic, bean-shaped, flask- 

 shaped or barrel- shaped; some cases have dorsal longitudinal ribs 

 (Figure 96). 



67) 



95 



FIGURES 95-97. Shape of the structures of Annulipalpia: 



95 —galleries, chambers and nets: gallery tube of Lype reducta (A), tube and 

 chamber of Wormaldia occipitalis (B), chamber and net of Hydropsyche 

 angustipennis (C); 96 - sacciform cases of Hydroptilidae: Ithytrichia la- 

 mellaris (A), Agraylea multipunc ta ta (B), Oxyethira costalis (C), 

 Orthotrichia tetensii (D); 97 - dorsal (A) and ventral (B) of a shieldlike case 

 ofMystrophora a 1 tai c a (95, A — after Hickin, 95, B — after Nielsen, 96 — after 

 various authors). 



The cases of Glossosomatidae which are covered with sand or small 

 stones resemble the pupal, cavelike cases of Rhyacophilidae, but the cases 

 have a ventral wall and two equal openings at the end (Figure 97); the larva 

 can turn around inside the tube, and each opening may serve as the anterior 

 or posterior opening. 



The portable case of the larvae of Integripalpia is usually a tube about 

 as long as the larva or slightly longer. The tube may be cylindrical or 

 conical, straight or curved, but it is dorsoventrally compressed. In species 

 of Thremma, the conical tube is very short and wider anteriorly, so that 

 67 the case resembles the shell of A n cylu s fluviatilis; in species of 

 Helicopsyche, the tube is spirally twisted like that of a snail. 



61 



