Localities in which Pellagra is Prevalent. 29 



longest, with a slight lobe on each side, outside it on each 

 side are five additional teeth gradually diminishing in size. 



Case brown, elongate, straight, or slightly curved, 

 gradually expanding to its open end, from the edges of 

 which arise six more or less bent cylindrical processes con- 

 tinued as ridges along the surface of the case. Processes 

 about half the length of the case, which measures 3.5 mm. 

 long, the expanded open end measuring 1 mm. in diameter. 

 Small cases are continued at the closed end into a slender 

 stalk, but as far as observed were attached by the side, 

 to stones, wood, and other objects, in the water. .The case 

 has an appearance of being composed of mud or refuse 

 glued together, and is very fragile. The longitudinal ridges 

 of the surface appear to be produced by building out the 

 open end of the case by adding material between the pro- 

 jecting processes. 



Dr. Johannsen's species was obtained from small 

 streams at Ithaca, New York. The case is, he says, com- 

 posed of silk, but those from Straight Creek are, as stated, 

 composed very largely of refuse. Differences between the 

 larva described by him and those collected by me are ap- 

 parently as follows : (1) The shorter antennae of the Ken- 

 tucky species (about half the length of the head) ; (2) the 

 acute appendages of the second antennal segment; (3) the 

 strongly pectinate median claws of the labrum. 



No. 2.— This is a second, cylindrical, elongate larva, 

 taken with others on the under surfaces of rocks in rapids 

 of the Left Fork of Straight Creek. It resembles the one 

 inhabiting the brown cases so much that it would by most 

 people be considered identical. The head is pale yellowish 

 brown, the two black specks of the sides of the head well 

 forward and contiguous, though a line separates them. 

 Antennse short, less than half the length of the head; first 

 division long, bearing a seta at its distal extremity, nearly 

 as long as all the rest of the antenna; second segment 

 without appendages; three small distal segments tapering. 

 Claws of the prolegs of the first body division numerous, 

 simple. Posterior clawed legs long and diverging. Two 



