« EelmineJätka »
generally over this area, what progress could this number of persons have made towards collecting or destroying them during the season? But let us see the condition after the invasion. A correspondent of the board writes :—"Having traveled over the largest portion of our county, I find that about three-fourths of our people are almost entirely desti. tute of food, fuel, and clothing. Some are now living on boiled wheat, and not half enough of that." And the report adds :-“ S. T. Kelsey thinks that 500 persons in Rice County will need assistance.” And now we may ask in what condition they were to devote their time in collecting grasshoppers' eggs, when want was staring them in the face. Had a liberal reward been offered by the State or general government, although they might have made but little progress in the work as compared with the amount necessary to be done to be effectual, still it would have done some good, and would have afforded at the same time some relief; and I believe that it is always best, when it can be done, to apply a remedy which will do good in one direction, if it fails in another.
[NOTE.—Since writing the above, many new facts in reference to the history and habits of C. spretus have been ascertained, and will be published in the report of the U. S. Entomological Commission; although in correcting proof now (1878), I bave preferred to allow what was written in 1875 to remain as it was, that the advance in our knowledge may be shown by comparison.]
Destruction of the larvæ and pupa.-A number of methods to accom. plish this desirable end have been tried and recommended, as rolling the surface in order to crush them, collecting and destroying them in various ways, burning, etc. There is no doubt but each of these methods will effect sometbing, and may well be tried, according to circumstances; and in thickly settled districts, where the larger portion of the land is under cultivation and the force at command comparatively strong, these means, and some others wbich are bereafter mentioned, may, and probably will, suffice to hold the enemy in check, especially if the farmers maintain their courage and fight the battle bravely and in concert. In thinly populated districts, and even where the larger portion of the land is not cultivated and the force at command is weak, the case is not so hopeful, as the surrounding uncultivated sections will furnish a new supply as rapidly as the previous one is destroyed. Professor Riley informs us that ditching as practiced in Western Missouri appears to be the most effective mode of defense adopted, and he thinks will prove a specific against the young. A ditch of the dimensions he gives—two feet deep and two wide, with sharply perpendicular sideswill doubtless prove an effectual barrier against the young larvæ, but the pupæ, though halting for a time, will soon make the leap, and then the column will press onward. But it must be remembered that it requires time to dig a ditch of these dimensions around an entire farm:
to protect a single field of forty acres requires a mile of ditching, or the removal of nearly 800 cubic yards of earth, which, in most cases, the farmer and his son or single hand will have to do.*
I have noticed the larger irrigating-ditches in Utab, with a watersurface from three to four feet wide, covered with wingless crickets (Anabrus simplex), which were floating helplessly onward; but although this was the case, the marching column passed on in its course with comparatively undiminished numbers. And in Utah and Colorado these ditches form but little impediment to the movements of the pupæ of the C. spretus. In the cool of the morning, in those mountain regions, the farmers frequently drive the semi-torpid young into the irrigatingditches, firing straw placed along one side to catch those that leap the ditch. But among the chief agencies in this work of destruction I am disposed to class birds and fowls, and to this end would recommend to the legislatures of the States suffering from these visitations the passage of stringent laws stopping entirely the destruction of all insect-eating birds, not for a portion of the year only, but for the entire year, and offering a premium for the destruction of rapacious birds. Let an officer be appointed in each district, if necessary, composed of four or five counties, whose duty it shall be to see that the laws are enforced, and who shall also experiment in introducing and multiplying the English sparrow or some other insect-eating bird of similar habits. It would be well, also, for the State and county agricultural societies to encourage the increase of domestic fowls as far as possible. Hogs should be raised, as they are not only fond of these insects, and also army-worms, but would also soon learn to hunt for the egg-sacks as they do for acorns in oak-forests. .
Driving into traps and ditches are remedies which have long been practiced. Scott in his “Excursions in Ronda and Granada”, as quoted by Kirby says:-" During our ride from Cordova to Serville we observed a number of men advancing in skirmishing order across the country and thrashing the ground most savagely with long flails. Curious to know what could be the motive for this Xerxes-like treatment of the earth, we turned out of the road to inspect their operations, and found they were driving a swarm of locusts into a wide piece of linen spread on the ground some distance before them, wherein they were made prisoners." Kirby adds in a note:-“ The same plan is adopted for the destruction of these insects in some parts of the United States; deep trenches being dug at the end of the fields, into which the grasshoppers are driven with branches, and then destroyed by throwing earth upon them." What has been beneficial heretofore may be so again, and because it is old is no reason for rejecting it for something new until thoroughly tried.
But without discussing further the various methods of defense against
* Subsequent observations have convinced me that the young locusts can be fought with a good degree of success, and that ditching is practicable and one of the best remedies that can be adopted.
the young, which experience and ingenuity, together with some knowledge of the insect, may devise, I must sum up the matter, and, after noticing some Acridian peculiarities of this season, close this note, which is already too extended.
1st. It is impossible to tell what may be done towards preventing their incursious into the border States until their history has been more thoroughly traced. This can only be done through the general government and with the aid of the military posts and stations.
2d. While it would be folly to undertake to exterminate them in their native haunts by destroying the eggs or the insects, yet, if it be possible to induce the Indian s by rewards to collect the eggs and young along the west side of the Plains, it would be wise to do so, and would, as a matter of course, do something toward diminishing them and keeping the Indian squaws at least employed, for I doubt exceedingly as to the male Indians doing much in this line, as they are so lazy.
3d. If it is found that the batching-grounds of the invading swarms are in the areas mentioned heretofore, it would be well for the government to give all its land of that section to induce immigration thereto, and the settlement, irrigation, and cultivation thereof.
4th. When investigation shows the usual batcbing-regions, if such there be, and lipe of travel, signal-stations connected by telegraph lines with the sections subject to invasion may do much good by giving warning of the coming locast storm.
5th. It would be wise for the people of Nebraska and Kansas to rely more upon wheat and root crops, as the hordes usually come too late to injure the former and can not so greatly injure the latter as other crops. But for the season after the incursion, when the young are expected to batch, this order will have to be somewhat reversed. This branch of the subject, I think, has not received the attention of the farmers of the border States which it deserves.
6th. It would be well for the States visited to offer rewards for the eggs and young, for although it might do but little fowards thinning the ranks of the pests it would do some good in this direction, and would afford a means of subsistence to the unfortunate.
7th. These States should make stringent laws protecting the insecteating birds, and adopt a method of enforcing them that would be car. ried out. It will pay them to employ a naturalist to determine those species which should be preserved and those for whose destruction a reward should be offered. In addition to this, farmers should raise an abundance of domestic fowls, which will furnish food as well as assist in destroying the locusts.
8th. It would be well for the farmers to raise more hogs wherever the grounds are protected by fences and they can be allowed to range.
9th. Ditching against the young larræ, and driving into ditches and fire, and such other local remedies as the situation and means at band may suggest, should be employed, and the farmer should bravely fight the battle.
Although the resulting brood generally proves more destructive in the mountain regions than the incoming storm, yet this does not appear so far to have been the case in the Mississippi Valley; and as a preventive or remedy for the original hordes dispenses with the necessity of battling with their progeny, it is against these the general government should direct its efforts in an earnest and determined manner.
From what is known of the habits of this species we may be assured that it will never become a permanent resident of the Mississippi Valley, as its sudden transfer from the dry and rarified air of the elevated mountain regions to the heavy and moist atmosphere of the States requires too rapid a change in its nature for it to undergo. But, sup. posing it should become habituated to this region and overcome all climatic difficulties, it is very probable, in fact I might say almost cer. tain, that it would lose its migratory disposition, and if but a variety of C. femur-rubrum, as I strongly suspect, would in all probability revert to that form.
The origin of the migratory habit of this species is an interesting question, and, I am inclined to think, is directly connected with the origin of the treeless plains of those western regions. If, as I have intimated, it is a variety of C. femur-rubrum, it is highly probable the latter appeared first in the older districts of the Atlantic area in its. present or some earlier form, and gradually extended west, and, as is. usual with the group to which it belongs, as it ascended to tbe colder regions of the Rocky Mountain Range, would have assumed the shortwinged form, unless prevented by some compensating cause. The repeated burnings of the prairies may have caused frequent removals, and thus bare given origin to its longer wings and migrating disposition, I am aware the question may be asked, Why did not the same thing occur with other species? But if the reader will carefully examine the list and localities of the United States Acridii, he will find but few spe. cies which belong to both the eastern and western regions; the belt which once formed the water-line north and south through the conti. nent forms a more distinct line between Acridian districts than even the Rocky Mountain Range, as I have shown in a former paper. But this is a question requiring a more thorough investigation than I can give it in this note, even had I the data necessary and felt able to do so with my limited geological knowledge. I therefore simply throw out the thought, to call the attention of others to the subject.
There is another fact presented this season in regard to this group of the Calopteni, to which I wish for a moment to call attention.
As shown in my Synopsis, and as confirmed by other entomologists, the chief difference between the spretus and femur-rubrum is the notch in the last abdominal segment of the male in the former and its absence in the male of the latter species, and the longer wings of the former.
Heretofore, the femur-rubrum, as thus inarked, bas always been our most common species in this section (Southern Illinois), and could, throughout the summer and fall and even during the spring, be found at any time in the fields and along the bighways; but, strange to say, this season that form has entirely disappeared, and has been replaced by a rather more slender form, with the last segment distinctly notched and the wings lengthened, resembling, and apparently identical with, Professor Riley's O. atlanis. How are we to account for this? It will not do to call it a hybrid between the spretus and the femur-rubrum, as the former has never been known to visit this region, at least in numbers sufficient to attract attention, the great army last season having penetrated but a sbort distance into the western side of Missouri. Nor will it do to say my examinations have not been sufficiently thorough, for I have kept watch of them during the entire summer, gathering hundreds, and, although finding some variation, have failed so far to find a single femur-rubrum.
I am also informed, by a letter just received from Professor Burril, of the Industrial University at Champaign, in this State, that since he noticed an article I recently published on this subject, he has paid some attention to the matter, and finds the same thing true there. I also observe a note in the last number of the American Naturalist, from Dr. Packard, mentioning the occurrence of spretus (probably atlanis) in Mas. sachusetts. Also the very fact that Professor Riley last year mentions the intermediate form, which he names as a new species, and which had never before attracted attention, coincides with the other facts I have men. tioned. Here, then, beyond dispute, a remarkable change is taking place, which gives rise to a number of important questions. And first of these is, What is the cause of this? I think it is owing chiefly, if not entirely, to climatic influences, and forms an index to the great changes in specific characters which may be effected by a change of climate. If I am correct in this, it follows that when the climate re. verts to its normal condition the species will do the same; and, on the contrary, if one should be permanent the other will also, in all probability, be the same.
I may also notice, as bearing upon this point, the fact (for since the publication of my recent article I have ascertained it is a fact) that Caloptenus differentialis Thos. has been seen in the central part of this State flying in bodies at considerable height, and apparently migrating.
Acridium emarginatum Uhl., a Western species, never before known to occur east of the Mississippi, has been discovered this season as far · east as Bloomington in this State. These facts are certainly important and instructive, and deserve careful consideration.
The chief practical questions connected with this subject, and which more directly concern our agriculturists, are these :-(1) Will invasions of the C. spretus grow more and more frequent? . (2) Will it continue to extend its limits farther and farther eastward? (3) Will the changes now taking place result in producing migratory hordes in our midst ?