Localities in which Pellagra is Prevalent. 7 



in which the water was not much over one's shoe-tops and 

 where it was possible to cross by stepping- from rock to rock. 

 One of these rapids just below the dwelling seemed to me 

 an ideal place for Simulium larvae, and a few minutes search 

 here brought to light some larvse and pupae. They were not 

 very common, however, and were so small that I felt some 

 hesitation about committing myself until they could be more 

 carefully examined. Examination, and in some cases dis- 

 section, made since my return to the University, leaves no 

 doubt as to their identity. 



On October 21, during a second visit to the region about 

 Pineville, I examined the Left Fork of Straight Creek well 

 up toward its source. Above the Coleman mining camp 

 were found larvae and pupee of -the same Simulium collected 

 on my previous trip. They were scattered and difficult to 

 find, and although not nearly so common as I have seen simi- 

 lar larvae in the spring of the year at other places, yet 

 judging by the frequency with which I found a few here 

 and there many of them must be now hibernating in the 

 creek. Most of the pupa cases were empty. Other speci- 

 mens were secured from rocks in the rapids of Cumberland 

 River at the point above Pineville where specimens were 

 secured in August and September. Numerous other insects 

 were found among the submerged rocks in Straight Creek, 

 Cumberland River and Clear Creek. Some account of them 

 is included in what follows, not because of any definitely 

 determined relation to the main object of my search, but 

 because some of them may later prove to have relations with 

 this and certainly have with other subjects of interest to the 

 people of the State. For it is to be remembered that it is 

 not certain that gnats of the genus Simulium have to do with 

 pellagra. It is possible that some other insect or animal is 

 concerned in its spread. 



Looking at the matter from the point of view of the en- 

 tomologist and naturalist it seemed to me very evident when 

 I had examined only a few cases of pellagra that some agent 

 in the air had to do with its spread, and it may be of in- 

 terest to recall the facts that most appealed to me. In the 



