﻿Observations on the Periodical Cicada. 



233 



In answer to an inquiry, Dr. Dun stated that one of the reasons for 

 assuming a distinction between the modern Indians and the Mound 

 Builders, was the mathematical knowledge displayed in the construction 

 of the mounds and earthworks, as well as the condition of mound-builder 

 bones, as compared with Celtic remains of a known age in Europe. 



Mr. J. R. Skinner stated that Col. Chas. Whittlesey had concluded 

 from a study of ancient remains that thirty inches was probably the stan- 

 dard of measure of the Mound Builders. 



OBSERVATIONS ON THE PERIODICAL CICADA. 

 By Walter A. Dun, M. D., M. R. C. S. 



I desire to present to your notice a few observations which I recently 

 had the opportunity of making on the Seventeen-year Locust in this 

 locality. 



The first place of observation was at Lindenthor, the residence 

 of Dr. E. Williams, situated on the top of the hill range on 

 the north side of the Ohio river, a couple of miles from the centre 

 of the city. The locusts began to make their appearance there on Friday, 

 May 28th, but only in small numbers. On Friday evening, immediately 

 after a rain storm, which moistened the ground considerably and possibly 

 aided the locusts to escape, they began to emerge from the ground in 

 large numbers, and crawl to the trees. It is interesting to note the fact 

 that they crawled up the tree often to as great a height as forty feet, and 

 upon this Friday evening, sought the under surface of both limbs and 

 leaves, where their shells were found the following morning. During 

 Friday night and Saturday morning they emerged from their shells and 

 remained about in a quiet way on the trees, apparently unable to make any 

 exertion. Saturday, Sunday and Monday evenings, May 29th, 30th, and 

 June 1st, respectively, similar hordes made their appearance, always late 

 in the afternoon, and mostly they were shell free before morning. On 

 these three later days, none of them being rainy, they never sought the 

 under side of the leaves and boughs, but seemed always to seek the upper 

 surfaces. Upon Tuesday, June 2d, a smaller quantity appeared. I left 

 on Wednesday, so can not say anything about their subsequent coming 

 there. Sunday, May 30th, they were first heard and their presence in 

 force certified to, by the peculiar hum which began about sunrise and grad- 



