Extracts from letters regarding Brazilian caddis-flies 1 ). 



(Letter to Mr. M'Lachlan.) 



Mr. M'Lachlan exhibited the cases and sixteen species of Brazilian caddis- 

 flies, with the insects bred from the larvae that manufactured some of them, sent 

 to him by Dr. Fritz Muller, from Santa Catharina. Included were the cases ex- 

 hibited at the meeting of the 4th December last. Some extracts (with notes) from 

 Dr. Fritz Muller's letters are here given : 



" 'Helicopsyche. In some cases of one of the species you will see, well pre- 

 served, the oldest part of the case, which peeps out like a chimney from the conical 

 top. There are here two or three other species of Helicopsyche, one of which 

 lives on rocks continually wetted by the spray of waterfalls: the pupa of this 

 species is deprived of the long hairs which exist, in other species, on the first 

 four joints of the fore and middle legs, and which the pupae, after leaving the 

 case, use in swimming to the surface. On the rocks it is, of course, neither 

 necessary nor possible to swim. Should not Brauer's Scetotricha be a HelicopsycJie ? 

 the neuration of the wings is very similar to that of our species 2 ). In the pupa 

 of Helicopsyche ceylanica, Brauer ('Voyage der Novara', Neuroptera) describes 

 the first joint of the maxillary palpi in either sex as being much shorter than the 

 second; but this is not the case with our species, which in their maxillary palpi 

 agree with Scetotricha. Perhaps there may not be any real difference in this 

 respect between H. ceylanica and the Brazilian species. Brauer's figure of the 

 palpi of HelicopsycJie looks as if there were something wanting at the base. 

 There are several other differences between the larvae and pupae of Helicopsyche 

 I have examined and Brauer's description of H. ceylanica ; whether they be real 

 or not I am unable to decide. The anterior margin of the pronotum of the larva 

 is armed, in our several species, with a row of strong spines, straight or curved 

 at the end. The branchiae described by Brauer I have been unable to find in 

 any of our species. The hooks at the apex of the abdomen are quite different 



1) Proceedings Ent. Soc. London 1879. p. VI VIII. 



2) I have already called attention to the probability that Scetotricha may be allied to Helicopsyche^ 

 in my 'Revision and Synopsis of European Trichoptera' (pt. V., p. 269, Nov. 1876). R. M'L. 



