Localities in which Pellagra is Prevalent. 23 



flowing into Kentucky River in the region about Clay's 

 Ferry about 15 miles southeast of Lexington. It was first 

 observed July 14, 1893. By simply closing the blades of 

 my forceps over the rocks in shallow water, then holding 

 them together and removing them, numbers of the larvae 

 could be picked up by the silken threads they emit as they 

 let go their hold and float down stream. They are true silk- 

 spinners like the other members of the genus. 



This is a very large species. Dr. Howard, writing of it 

 in Insect Life (Vol. 1, p. 99) says of examples collected by 

 him at Ithaca, New York, that some of them measured 

 three-fourths inch in length. I have none from our streams 

 as long as this, but the larv£e are much larger than the 

 others collected in this State. 



Adult male.— Br. Johannsen in an article published in 

 Bulletin No. 68, N. Y. State Museum describes the male as 

 gray, the antennae and palpi black; the metanotum with 

 golden pubescence, black, with lateral margins gray, and a 

 gray spot extending inward from each humerus; a pair of 

 silvery spots within the gray ones. Beneath gray. Abdo- 

 men deep velvety black. Legs black or dark brown. Knobs 

 of balancers, orange-yellow. Length 3.5 to 4 mm. 



Adult female. —The same author describes the head and 

 thorax of the female as opaque gray, the metanotum with 

 three deep brown or black stripes; abdomen velvety black, 

 beneath gray. Legs grayish or pallid; tips of tibiae and 

 tarsi generally black. Knobs of balancers yellowish white. 

 Length 3 to 5 mm. 



Larvae in numbers were collected and preserved in 

 alcohol in 1893. The largest measure about eleven milli- 

 meters in length, and are blackish, excepting the head, 

 which is reddish brown, and the ventral side of the swollen 

 posterior region of the body, which is white. Head of a 

 decided reddish brown, the large brushes of strongly ciliate 

 setae of the same color. The usual pair of black specks on 

 the side of the head, in a pallid area. Antennae of three 

 segments, the basal long and a little curved, with some ap- 

 pearance of being subdivided; second segment straight and 



