Emergence to land. The pupae of species living among humid moss 

 or plants near the water surface do not swim; they crawl from the water on- 

 to plants or stones, e. g. , some species of Sericostomatidae and Lepidosto- 

 matidae (Notidobia ciliaris, Crunoecia irrorata); the pupae of 

 these species do not have swimming legs. 



FIGURE 164. Movements of the mandibles of the pupa 

 of Hydropsyche sp. when it tears the membrane 

 (after Sattler) 



103 



The swimming pupae also crawl or climb on the land, remaining in the 

 water only until they reach an object to which they can cling so as to leave 

 the water. The pupae climb on stalks of plants or grasp stones or the sand 

 of the shore. The pupae of most groups living mainly in running water 

 use their claws to leave the water. The claws are well developed in the 

 pupae of Rhyacophilidae, Philopotamidae, Psychomyiidae and Polycentro- 

 podidae; among the Integripalpia, they are developed in Phryganeidae and 

 some species of Lepidostomatidae (Lasiocephala basalis, Crunoecia 

 irrorata). The pupae of some species of Baicalinini (Apataniinae) leave 

 the water in large numbers in early spring through cracks in the ice (Gusev, 

 1956); mass emergence is also characteristic for many species of Hydro- 

 psychidae and Hydroptilidae. 



Hatching of the imago. Some small species hatch by flying up 

 directly from the water; however, the last molt usually takes place on the 

 shore. The pupa crawls on the ground or an object projecting from the 

 water and becomes dry. When the molt begins, a slit appears on the dorsum 

 of the thorax, reaching the base of the head; the antennae become free, and 

 then the insect extracts the fore- and midlegs; the insect then frees its 

 wings and hind legs and discards the exuviae by movements of the abdomen; 

 it spreads its wings, makes a few steps and then halts and breathes 

 energetically; the wings soon attain their pattern and coloration, and the 

 insect flies off. 



Trichoptera hatch in masses (like mayflies) in large water bodies 

 inhabited by larvae which develop at about the same time, e. g., in large 



94 



