486 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



C. femur-riihrum, C. atlanis, G. occidenialis, and C. spretus but varieties 

 of one and the same species ? 



Most of these are important questions, and deserve a more careful 

 consideration than I am at present able to give them, not only for want 

 of time, but also for want of the proper data. Before this can be done, 

 the whole subject will have to be more thoroughly investigated; and as 

 the region over which these winged messengers of destruction roam is 

 very extensive, and much of it unoccupied, except by savage Indians 

 and a few military posts and stations, this investigation can only be 

 properly made under the sanction and with the aid of the national 

 government. It will be absolutely necessary to have the aid of the 

 military posts as points of observation, and hence could probably be 

 best performed under the military department. I will only attempt in 

 this note to give some facts and opinions bearing upon some of the 

 points mentioned. 



First. Are there any means of preventing the migration of these lo- 

 custs"? It is evident that if they are all destroyed, this will prove a spe- 

 cific against future migrations. To do this^our attacks must be directed 

 chiefly against the eggs and the young in their native haunts or hatch- 

 ing-grounds. Is this practicable? If their total destruction is not pos- 

 sible, the next important inquiry is, Can the eggs or young be destroyed 

 in the hatching-grounds from which the swarms come that devastate 

 our border States ? In order to answer this question correctly, it is 

 requisite that the swarms which visit these States be traced positively 

 to their original hatching-grounds. Although Arabia and Central Asia 

 are given as the native habitats and hatching-grounds of (Edipoda mi- 

 gratoria, yet after a somewhat careful search of the records I have not 

 been able to find a single instance in which a horde visiting Europe has 

 been traced positively to its original hatching-grounds in these regions 

 from which they are supposed to have come. Even as late as 1836, 

 Serville had to confess that though the locusts had been a plague for 

 thousands of years, yet their habits and history were not well under- 

 stood. Koppen's late investigations in regard to this species, though 

 valuable, appear to throw but little additional light upon its history. 

 Here the starting-points and the termini of the migrations of these 

 locusts are within our own territory, no part of which is inaccessible to 

 man, while a very large portion of the West is traversed by railroads 

 and telegraph lines. Military posts and stations are here and there in 

 the area not occapied by settlements. It is therefore certainly possible 

 by proper effort to trace their movements from one extremity to the 

 other. 



Let us now for a moment inquire ioto the possibility, or rather prac- 

 ticability, of utterly exterminating these insects by destroying their 

 eggs and young in their native haunts. 



Their hatching-ground is known to extend over the vast area roughly 

 designated by the following boundary lines : — On the east, the 103d 



