﻿OP THE STATE ENTOMOLOGIST. 145 



future by the past, I drew particular attention to the last question, as 

 one not answerable from my own individual observation, as most of 

 the others are. The replies to the above questions have been very 

 full, for which fact I must again thank the gentlemen mentioned on 

 pp. 51-2, ante. From these detailed reports, I have constructed the 

 accompanying map* which indicates, 1st, the counties invaded in 1866, 

 marked with a small cross ( + ) ; 2nd, those invaded in 1874, and the 

 eastern limit reached, marked by ruled lines ; 3d, the general direc- 

 tion from which the insects came, marked by the direction of the lines 

 and by arrows. The answers to the different questions have been prop- 

 erly tiled and arranged by counties, and will be preserved. They are 

 too voluminous to publish, and it is sufficient here to give a summary 

 of them, numbered to correspond with the questions. 



1 — This question is suflSciently answered on the map, from which 

 it will be seen that 35 of our western counties were invaded, and that 

 they reached farthest into the State in Benton and Pettis. 



2 — The general direction from which they came was from the 

 northwest, the reports showing remarkable agreement in this respect. 

 The greatest deviation from this course occurred in the more eastern 

 or last counties visited, when the army became pretty well thinned 

 out and demoralized, and flew about with less uniformity, being more 

 governed by the wind. The dates at which they are reported from 

 the different counties are interesting, and show that the insects ad- 

 vanced at an average rate of not more than three miles a day. That 

 they travel at a far greater speed, everyone who has witnessed their 

 migrations is aware, and this low average rate is due to the fact that 

 they fly only during the heat of the day and on certain days when the 

 wind and weather are favorable, and to the further fact that the insects 

 were no longer as vigorous and numerous as they had been in 

 the country to the west. Another interesting fact is deducible 

 from the returns, viz.: that the rate of advance was greater in 

 the counties first invaded than those last reached — a fact indicating 

 that the insects were getting more and more exhausted and less 

 desirous of flight the farther east they came. They reached Holt 

 county on the 8th of August, and all the counties on the same line, 

 north and south, from Worth to McDonald, were reached during the 

 latter part of the same month. They then continued to make short 

 flights, and finally reached their extreme eastern limit toward the 

 last of September. 



3 — The correspondents do not agree as to whether the wind has 



* Where the map does not accompany this page it will be found in front of the Volxmie. 

 ER— 10 



