When a mature larva of L. flavicornis is removed from the case, it 

 first crawls about restlessly for some time, and then builds a temporary 

 case. This consists of several thin bands around the body which are 

 connected with each other at some points. The material of the outer layer is 

 glued to the bands irregularly; the larva does not use large particles and 

 does not prepare them; it usually uses ready, soft material. The definite 

 case is completely different; the sheath is thick, forming a strong tube 

 from which the particles of the outer layer can be removed without damage 

 to the tube. The larva arranges the fragments in the form of a thick, 

 continuous layer. It usually builds the case from pieces of reeds and cane; 

 and it prefers spruce needles to pine needles. 



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FIGURE 113. 1st stage larvae of Li mnophi lu s nigri ceps in temporary 

 cases 



Building takes place as follows: the larva holds a fragment of detritus 

 with its fore and midlegs; it places the fragment near the anterior margin 

 of the case, then it smears the fragment at the inner and outer sides with 

 the secretion of the spinning glands; at the same time it prolongs the 

 secretion-made tube by a length corresponding to that of the fragment. The 

 time used for building shows that the building of the definite case is more 

 complex than that of the temporary one: under experimental conditions, the 

 75 larva of L. flavicornis needs 6—8 hours to build a temporary case, 

 but it needs 8 — 10 days to build the definite case. When this is ready, the 

 larva turns about inside the case, bites off the temporary case and weaves 

 the membrane of the posterior end which has a round opening in the middle; 

 the larva then resumes its normal position (Gorter, 1931). 



The building of the case from sand was studied in detail in Molanna 

 angustata Curt. (Dembowsky, 1923, 1933). The case of Molanna is 

 complex, consisting of a tube, a broad anterior hood and wings (Figure 114, B). 



When removed from its case, the larva of Molanna crawls restlessly 

 on the bottom for some time and then begins to dig itself into the sand, 

 stirring it with movements of head and forelegs; gradually the larva buries 

 itself in the sand. It then turns on its back and by movements of the 

 abdomen throws particles of sand to the anterior part of the body; it catches 

 them with the legs, smears them with secretion (see spinning glands in 

 Figure 114, A) and makes a coil of threads in which many particles are 

 entangled. When this coil is sufficiently large, it is used as a supporting 

 base to which the first ring of the new case is attached (Figure 114, C). 



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