Notes oil the Cases of some South Brazilian Trichoptera. 



Rhyacophilid?e. 



Genus I. 



(Spurs of a d pupa 2, 4, 4.) 



The larva lives, principally, without any case, between the etangled stems 

 of various Podostemece, which densely cover the stones in the rapids of the 

 Itajahy and its tributaries. It is carnivorous, fragments of insect larvae (Hydro- 

 psychidcpy Perlidce, &c.) being found in its intestines, and its anterior legs are 

 armed with very powerful and curious forceps; the femur is very thick, and has 

 on its distal inferior angle a stout process, resembling the thumb on the hand of 

 a crab; the tibia and tarsus are extremely short, so that the curved claw im- 

 pinges against the process of the femur. The cocoon of the pupa, also, is not 

 protected by a regular case; sometimes there are some loosely-connected stones 

 around it, but at other times it appears to lie, without any special protection, 

 between the Podostemecv. The feet of the first and second pair of legs are pro- 

 vided in the pupa with strong well-developed claws, which I have not yet seen 

 in any other Trichopterous pupa. They are, probably, very useful to the pupa 

 of this species, which has to make its w 7 ay between the densely-intricate stems of 

 Podostemece. 



Genus II. 



The larvae of some smaller species of Rhyacophilida' build portable cases, 

 agreeing with those of most Hydroptilidcr in not showing any difference between 

 the two extremities. They are built of stones, oval, with a flat bottom, on either 

 end of which there is an opening; the stones generally being of comparatively 

 large size, the external aspect is often very irregular. As the two doors of these 

 little stone-houses are in the flat bottom, they would not freely admit the water 

 necessary for respiration, when the larva is at rest, and there are special contri- 

 vances for the access of water varying in the several species. In one species, 

 frequenting small mountain rivulets, small passages are left between the stones 

 of the dorsal side of the house. In another species, which often covers by count- 

 less thousands the stones in clear streams, an upright cylindrical chimney, made 

 of grains of sand, rises from the middle of the house; its height sometimes equals, 

 or even exceeds, the length of the house. When the larva is about to change, 

 the bottom and chimney are removed, the borders of the vault are fixed to the 

 stone, on which it lives, and then a cocoon of the usual form is spun. 



Hydroptilidae. 



In Hagen's list of South American Neuroptera (Synopsis of the Neuroptera 

 of North America, 1861, p. 299), no species of this family is mentioned, and yet 

 it will probably prove to be one of the most numerous Trichopterous families in 

 this country, including the most varied and remarkable larval cases. 



Genus I. 



There are here various species, the cases of which resemble more or less 

 closely the well-known cases of Phrixocoma pulcliricornis, being much com- 

 pressed from the sides and opened by a narrow slit at each end. They are either 



