Notes on the Cases of some South Brazilian 



Trichoptera 1 ) 2 ). 



Little is known about the cases of extra-European Trichoptera. A short ac- 

 count of those observed by me in Southern Brazil may therefore be of some 

 interest. 



Of the seven families into which Trichoptera are at present divided, only 

 five have as yet been found here, viz., Sericostomida; , Leptoceridcc, Hydro- 

 psychidcc, Rliyacophilidce and Hydroptilidce. These may be grouped into two 

 main divisions according as their pupae are active or inactive. In the first group 

 comprising the Sericostomidce, Leptoceridcc and Hydropsychidce, the case of the 

 pupa is provided with small openings at cither end, through which a continual 

 current of water passes moving from the anterior to the posterior extremity. The 

 pupa is in incessant activity to maintain this current; this is done, at least in 

 most species, principally by the appendages at the end of the abdomen, which 

 may be seen playing in the opening at the hind-end of the case. In the second 

 group, containing the Rhyacophilidce and Hydroptilidce, the larva spins a cocoon 

 closed all around, in which the pupa lies quite motionless. This cocoon is either 

 free within the case (Rhyacophilidce}, or confluent with the walls of it (Hydro- 

 ptilidce). The fixity or mobility of the cases does not afford a distinctive character 

 of the two last-named families; for there are not only Rhyacophilideous larvae 

 living in portable cases and Hydroptilideous larvae living in fixed ones, but there 

 are even cases fixed and movable at the same time, being fastened by a long 

 flexible string (Rhyacopsyche). 



Sericostomidse. 



This family, as far as I know, is here represented only by the curious genus 

 Helicopsyche, of which 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 pre- 



1) Trans Ent. Soc. London 1879. p. 131 144. 



2) Figures and full descriptions of the cases mentioned in the following notes have been sent for 

 publication to the "Archives do Museu Nacional do Rio de Janeiro". (= Ges. Schriften S. 644 ff.) [Some 

 additional notes appear in the Report of the Proceedings of the Meeting of the Entomological Society, 

 held on the 2nd April, 18/9; cf. Proceedings, pp. vi viii. (= Ges. Schriften S. 762) ED.]. 



