Notes on the Cases of some South Brazilian Trichopleni. y - I 



naked, or covered with very fine sand, or with algae or diatoms, which in one 

 species are arranged in an extremely elegant manner. The cases of the pupae 

 are fixed either along the whole ventral margin or at the two ends, or in one 

 species, abounding on the rocks of waterfalls, at one end only. 



Genus II. 



Very minute, nearly cylindrical, coriaceous, brown tubes; covered with very 

 fine sand, which in the pupa state are fixed at either end to the underside of 

 stones, showing generally two adhesive discs on the anterior, and a single one 

 on the posterior end. They are common almost everywhere. 



Genus III. Diaulus Ladislavii. 



Strongly-compressed oval cases, elegantly covered with diatoms, with a 

 narrow slit at each end and having on the dorsal margin two (or, as I have seen in 

 one specimen, three) cylindrical chimneys. The observation of living larvae of 

 this and of the first genus leaves no doubt as to the use of the chimneys. Those 

 inhabiting cases opened only by a slit at each end are seen moving incessantly, 

 and working very hard, in order to maintain a current of water through these 

 narrow passages; those of Diaulus, on the contrary, may remain motionless for 

 a very long time, the water necessary for respiration having a free access through 

 the chimneys. The cases of the pupae are fixed in an upright position along the 

 whole ventral margin on the upper side of stones, and often these little houses 

 form large villages of a rather picturesque aspect. 



Genus IV. Lagenopsyche. 



An approximative idea of the cases may be formed by imagining the bottom 

 of a bottle to be cut away and then its under part to be compressed until the 

 opposite sides touch each other, thus transforming the wide circular opening into 

 a narrow slit. The mouth of the bottle represents the mouth-end of the larval 

 case, and trie long narrow slit at the tail-end is held in an upright position. In 

 one species (L. hyalina] the case is quite colourless and perfectly hyaline; in a 

 second species (L. Spirogyrce) it has a dark violet, or brownish, or blackish, colour, 

 darker towards the mouth-end. For transformation the case is placed on one of 

 its broad sides, and then fixed on either side of each end by means of petiolated 

 discs; at the mouth-end of the larval case there are two discs in both the species, 

 and as many exist at the opposite end in L. Spirogyrce, but in L. hyalina there 

 are four, the petioles dividing before they expand into discs. After having fixed 

 its case the larva turns its head towards the broader end of it, so that the mouth- 

 end of the larval case becomes the tail-end of the pupa case, and vice versa. 

 L. hyalina lives in small rivulets under stones, L. Spirogyrce in slowly-moving or 

 even standing waters filled with Spirogyra, Cattitriche and Heter anther a reni- 

 formis ; the larvae are to be met with among the Spirogyrce, on which they seem 

 to feed; the pupae are fixed to the under side of the leaves of Callitriche or 

 Heter anther a. The perfect insects emerge early in the afternoon. 



Genus V. Rhyacopsyche Hagenii. 



The larva? live in rapids of mountain rivulets. The brown coriaceous cases 

 of younger larvae are nearly cylindrical and widely open at each end, afterwards 



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