132 Dr. Fritz Miiller's Notes on the Cases 



SERICOSTOMATID^. 



This family, as far as I know, is here represented only 

 by the curious genus Helicojosi/che, of Avhich I have seen 

 about half-a-dozen species. The case of one species is 

 remarkable for the first built portion of it being straight. 

 When preserved in adult specimens, this oldest portion 

 peeps out from the top of the heliciform case like a little 

 chimney. Most of the larvse of Helicopsyche are rather 

 sluggish animals, often resting motionless on the same 

 spot for the whole day ; they then retire into their cases 

 after having fixed them temporarily with some threads of 

 silk, a custom which is to be observed also in various 

 Leptocerideous larvae. In none of our species have I 

 seen branchiae, which, according to Brauer, exist in 

 Helicopsyche ceylanica. Before passing into the pupa 

 state, the larva shuts its case with a flexible corneous 

 covering, provided in most of our species with a long, 

 simple transverse slit ; in one species the margins of the 

 slit are serrated, and in another species there is no slit at 

 all, but a sieve-like spot near the centre of the covering. 

 As to the pupa3, Brauer says, that those of H. ceylanica 

 have a pair of hook-bearing corneous patches at the basis 

 of the abdominal segments from the second to the sixth, 

 and there are also five pairs in his figure. This would be 

 very strange, for the number and shape of these patches 

 is generally very constant within the limits of the same 

 genus, and in all our species f ' Helicopsyche there are four 

 pairs only, situated at the b sis of the third, fourth, fifth 

 and sixth abdominal segments ; each patch bears near its 

 posterior end two or three short, rather blunt teeth, which 

 are directed backwards. There is also, as usually, a pair 

 of corneous patches at the end of the fifth abdominal seg- 

 ment, armed Avith strong, sharp, curved teeth, which are 

 directed forwards. 



One of our species of Helicopsyche lives on rocks wetted 

 by the spray of waterfalls ; it is by far more lively than 

 the other species. The Avaterfalls, which are of very 

 frequent occurrence in all our mountain rivulets, are 

 generally frequented by three more species of Trichopte- 

 rous larvffi, belonging to three different families {Leptoce- 

 ridcB, Hy dropsy chidcB and Hydroptilidce). Now the pupee 

 of those four widely-different species agree in their feet of 

 the second pair of legs being deprived of the fringes of 



