— 36 — 



surely a certain force is needed for the pushing out the band 

 which is growing by and by at its end. When a hcst case with 

 a still growing band is opened the Agriotypus-larva. will always 

 be seen to lie close to the anterior end of the case and having 

 the anteriorly truncate and posteriorly pointed form. 



In crder to élucidai the function of the band G. W. MûL- 

 LER (I) eut off the band in a certain material, the resuit was 

 that 91 % of thèse bandless spécimens died (while the mortality 

 for the intact cases was 38 %). A new experiment of his showed 

 100 % dead when no band was présent (and 47,4 % when the 

 band was intact). 



As a supplément to thèse experiments also I hâve experi- 

 mented cutting of bands. Unfortunately I had only 12 cases 

 at my disposai (while MùLLER had 91 and 190), they were 

 arranged by two under 6 différent conditions of life in 3 months 

 (between20/7 and 27/10). 



The resuit was the f ollowing : 



1 . Band intact : aquarium constantly furnished with fresh water 

 (normal conditions): 27/10, the two cases centained 1 living 

 imago and 1 living pupa about to cast the pupal skin. 



2. Band intact; Water in aquarium was stagnant and never 

 changed, at last it smolt very foui and was filled with Sapro- 

 legnias : 27/10, 1 living ycung pupa and 1 mature living larva 

 were found. 



3. Band intact; the cases were kept dry : 27/10, 1 living imago 

 and 1 living pupa were found. 



4. Band eut eff : aquarium constantly furnished with fresh 

 water : 27/10, were found 2 dead larvae (cne dead rather newly, 

 one quite decayed). 



5 . Band eut off ; water in aquarium never changed (as No 2) : 

 27/10, 2 dead and decayed larvae were found. 



6. Band eut off; the cases were kept dry : 27/10, in one case 

 a larva dead long ago, in the other a living chitinized imago 

 were found. 



As will be seen from the experiments by MùLLER and by me, 

 the band must be of vital importance to the Agriofypus-larva., 

 at any rate when the case is lying in water, and no doubt can 

 be that it serves the respiration. When the larvae die during 



(I) Zool. Jahrb. Abt. Syst. IV, 1889, p. 1132, und V, 1891, p. 



689. 



-^ *" 



