7 54 Notes on the Cases of some South Brazilian Trichoptera. 



served in adult specimens, this oldest portion peeps out from the top of the helici- 

 form case like a little chimney. Most of the larvae of Helicopsyche arc 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 ser- 

 rated, and in another species there is no slit at all, but a sieve-like spot near the 

 centre of the covering. As to the pupae, Brauer says, that those of H. ceylanica 

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

 ments 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 of 

 Helicopsyche there are four pairs only, situated at the basis of the third, fourth, 

 fifth and sixth abdominal segments; each patch bears near its posterior end two 

 or three short, rather blunt teeth, which arc directed backwards. There is also, 

 as usually, a pair of corneous patches at the end of the fifth abdominal segment, 

 armed with 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 waterfalls, which 

 are of very frequent occurence in all our mountain rivulets, are generally frequented 

 by three more species of Trichopterous larvae, belonging to three different families 

 (LeptoceridcB, Hydropsychidce and Hydroptilidce). Now the pupae of those four 

 widely-different species agree in their feet of the second pair of legs being deprived 

 of the fringes of long hairs, by the aid of which the pupae of other Trichoptera 

 swim to the surface of the water when they are about to undergo their final 

 transformation. 



In those species of Helicopsyche, which I have bred, the perfect insects used 

 to emerge from the pupae soon after sunset. 



Leptoceridse. 

 Of M'Lachlan's first section of this family I have not yet seen here any species. 



Section II. 

 Two of our genera appear to belong to this section. 



Genus I. 



(Near Odontocerum, though distinguished by numerous differences. Antennae 

 not dentate ; eyes of the <$ very large, meeting on the vertex in one species 

 and nearly so in another; radius of the anterior wings confluent at its 

 apex with the first apical sector, &c.) 



The case of the larva is a slightly-curved, cylindrical, firm tube, built with 

 sand grains; the tail-end is closed with a transverse wall, having at its upper or 

 dorsal margin a rather large oval or semicircular opening. Before its change the 



