The species of Leptoceridae, living in stagnant water, attach their tubular 

 cases to a plant before pupation (Figure 149); they place the anterior and 

 posterior membranes within the tube, some distance from the case margin; 

 there is a small opening with outward projecting margins in the middle of 

 the membrane (Figure 155). In species with a short, broadly conical pupal 

 case, e. g., in Leptocerus senilis, the case has an anterior transverse 

 slit and a round opening posteriorly; the cases of L. annulicornis and 

 L. excisus have long anterior and posterior transverse slits. 



The pupal cases of the family Goeridae are covered anteriorly with a 

 small stone bordered with a narrowband of membrane with slitlike 

 openings; the membrane has similar openings posteriorly in its ventral 

 part (Figure 156); in pupae of the Sericostomatidae, the anterior membrane 

 contains a transverse slit, and the posterior membrane a longitudinal slit 

 (Figure 157); in the Brachycentridae, groups of small openings are 

 concentrated in the middle of the anterior and posterior membranes 

 (Figure 158). 



After the case is closed, the prepupa and the pupa usually remain in the 

 same position as during the larval stages; this position is changed in some 

 cases, e. g.,in Molanna angustata, the dorsal side of the pupa is 

 directed toward the ventral side of the case, which is connected with the 

 position of the openings of the membranes of the case and the cleaning 

 apparatus of the pupa (Figure 162). 



Molting. After the case has been attached and closed (after the 

 weaving of the cocoon in Annulipalpia), the larva passes a prepupal diapause 

 and then molts into the pupa; in some species, e. g., species of the tribe 

 Baicalinini, the prepupal diapause is very long, lasting several months. The 

 shed exuviae are usually destroyed, but the sclerites are preserved in the 

 cocoon of Annulipalpia or in the tube of Integripalpia; This makes it possible 

 to identify larvae and pupae of the same species. The larval sclerites are 

 especially well preserved in the closed cocoon of Rhyacophilidae; the 

 sclerites are visible through the semitransparent walls of the case as a 

 dark mass in the posterior end of the cocoon. Preparations of fully 

 developed genitalia of the imago, can be made from a pupa ready to hatch, 

 so that the species can be identified. 



Life of the pupa inside the pupal case 



During most of the pupal stage (which lasts 7 to 28 days or longer), the 

 pupa moves little; only at the end of the pupal stage, before hatching, does 

 100 the pupa swim or remain in the air for a short time, several minutes or less. 

 During the histolysis in the pupal stage, small groups of muscles are 

 retained which enable the insect to make some movements; these move- 

 ments ensure respiration inside the chambers and tubes. This is attained 

 by undulating movements of the abdomen in the Integripalpia and some 

 families of Annulipalpia (Polycentropodidae, Arctopsychidae, Hydro- 

 psychidae). The undulating movements in the tube create a current from 

 the anterior to the posterior ends of the case; the abdomen and gills of the 

 pupa are thus washed continuously by fresh water (Figure 159). The 



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