Notes on the Cases of some South Brazilian Trichoptera. 7 6 S 



larva cuts a portion of the tail-end of its tube and then fixes the ventral side of 

 either end and closes them by a single stone (in one species), or by a wall built 

 of several fragments of stone (in a second species), in such a way that there 

 remains at the ventral side of each extremity a narrow crescentic slit, the ventral 

 margin of which is beset with a row of teeth. It is curious that the; manner of 

 closing the tail-end should be quite different in the larva and in the pupa cases. 

 The pupa has five pairs of corneous patches at the basis of the abdominal seg- 

 ments (from third to seventh), each of the patches bearing a single blunt tooth, 

 and there is the usual pair of patches at the end of the fifth segment, having 

 two short sharp teeth. 



The perfect insects emerge from the pupae in the evening, generally later 

 than Helicopsyche. On this occasion the fasciculate branchiae of the pupa are 

 shed, like those of Ephemeridce, and this is the most remarkable feature of the 

 genus; for it appears, that in most Trichoptera the branchiae of the pupa subsist 

 in the imago in a rudimentary condition. 



There are here two species of this genus, differing much in size, the larvae 

 of which live in clear rivulets; a third species of larvae, building unusually short 

 and wide tubes, of which I have seen but hery few specimens in the River 

 Itajahy, probably belongs in the same genus. 



Genus II. Grumicha, of Saint Hilaire. 



The wings having no median cell, the insect cannot be placed in M'Lachlan's 

 fourth section, while, by the moderate length of the antennae and the presence 

 of the apical fork, No. 2, in all the wings it is excluded from Section III. Thus 

 I place it here, though it shows no particular relation to Odontocerum. (Spurs 2, 2, 2. 

 Discoidal cell closed, and radius connected to the first apical sector by a trans- 

 verse nervule in all the wings. Apical forks, Nos. i, 2, 3, 5 in the anterior i, 2, 5 

 in the posterior, wings.) The wellknown black Dentalium-like tubes of the larvae 

 are frequent in some of the larger tributaries of the Itajahy. The larvae are re- 

 markable for the tibiae of the hind legs consisting of two joints. The tail-end of 

 the tube is closed with a transverse wall, having a central circular opening. 

 Before its change the larva fixes the mouth-end of its tube by a petiolated disc 

 to some stone or to other tubes of the same species. Clusters of more than a 

 hundred specimens are sometimes found. The mouth-encl of the tube is closed 

 with a circular covering, provided with a transverse opening beneath its centre. 



Section III. 



Genus I. Tetracentron, Brauer. 



One species of this New Zealand genus is extremely common here. The 

 larva, which, like those of Grumicha, have two-jointed tibiae on the hind legs, 

 lives in sticks of wood, fragments of branches, of petioles of Cecropia leaves, &c. 

 These are hollowed out in convenient lengths, and a semicircular piece is cut 

 away from the ventral side of the mouth-end, so that the dorsal side projects, 

 protecting the larva when crawling about; besides this, for more protection, a 

 small stone is fastened to the projecting dorsal side, which closes the entrance 

 when the larva retires into its case, and covers its head when feeding. Near the 



