3IO 



NATURE 



[Feb. 6, 1879 



Chapter III. gives "Statistics of Losses." The esti- 

 mate of losses is made by taking a "locust year" for 

 comparison with one when there was no locust visitation. 

 Dr. Hayden in his letter to the Secretary of the Interior, 

 which accompanied the Report, has thus summarised it. 

 The great practical importance of an exhaustive study 

 of this destructive insect throughout all the immense 

 extent of the locust area, which lies between the 94th and 

 120th meridian, embracing nearly two million square 

 miles, may be realised from the fact that on a careful 

 estimate from all the data obtainable, the States and terri. 

 tories'lying west of the Mississippi and east of the great 

 plains, suffered by the depredations of the locusts an 

 aggregate loss in destruction of crops alone during the 

 years 1874-77 of 100,000,000 dols., to say nothing of the 

 indirect loss by stoppage of business and various enter- 

 prises which must have been as much more, thus making 

 the direct and indirect losses at not less than 200,000,000 

 dols. 



Chapter IV. (pp. 123 to 131) is occupied with con- 

 sidering the agricultural bearing of the locust problem, 

 points out what crops suffer most, and discusses what is 

 likely to be the effect of agiicultural operations in the 

 future. Such precautions as accurately knowing the 

 dates of invading swarms and planting early or late 

 accordingly are referred to. 



Chapters V., VI., VII. (pp. 131 to 212) are occupied 

 respectively with an account of observations on the 

 *' permanent breeding grounds," the " geographical dis- 

 tribution," and the " migrations " of the Rocky Mountain 

 locust. Previous to 1877 very little was known of the 

 breeding grounds. The Commission has been able to 

 map the area and also map the districts subject to in- 

 vasion, while the directions taken by invading and return- 

 ing " armies " are also given. It is found that, as a rule, 

 flight is undertaken only during a part of the day and in 

 fair, clear weather, so that the desire for food, cloudy or 

 rainy weather, and adverse winds, may keep them from 

 rising and taking wing. In all flights it seems the locusts 

 rely much on the wind to carry them, usually turning 

 their heads towards the wind and drifting backwards. 

 When the wind is slight, however, they use their wings 

 and turn their heads forwards. Their flights can be 

 continued for several days over a distance of several 

 hundred miles. The rate at which they travel ij 

 variously estimated at from three to fifteen or twenty 

 miles an hour, determined by the velocity of the wind. 

 There are facts which show that they can fly two miles 

 and a half above the general surface of Kansas and 

 Nebraska, and far out of sight of the keenest vision. 

 This will explain their often sudden and mysterious ap- 

 pearance in areas without anything having been seen of 

 them on the line along which they travelled. Sometimes 

 two swarms have been seen moving in opposite direc- 

 tions, one in an upper and one in a lower current. With 

 regard to the return migrations, the Commissioners re- 

 mark that they are led to the conclusion " that by some 

 law governing them there is a tendency in the resulting 

 broods hatched in this visited area to return to the native 

 habitats from which their progenitors came." The con- 

 nection of meteorological phenomena with migration is 

 entered into at considerable length, and many pages of 

 meteorological data are g^ven. 



Chapter VIII. (pp. 212 to 257) is devoted to habits and 

 natural history. Various observations are collected as to 

 the quantities of eggs laid and the conditions of hatching. 

 The laying season is from six to eight weeks ; the average 

 interval of laying is two weeks, and the average number 

 of egg-masses is three. The idea that locusts are led by 

 kings or queens is unfounded. The reasons assigned for 

 migrations are (i) hunger, (2) the desire to find fresh 

 breeding-grounds, (3) to escape natural enemies, (4) " in- 

 stinctive impulse." Though by choice their food is the 

 various cereals, they will eat almost anything at a push, 

 even "dry leaves, paper, cotton and woollen fabrics. 

 . . . They do not even refuse dead animals, and have 

 been seen feeding on dead bats and birds." They often 

 strip fruit trees of their leaves. " Forest and shade trees 

 suffer in different degrees, and some, when young, are not 

 unfrequently killed outright." At the end of this chapter 

 reference is made to unnecessary alarm often caused by 

 comparatively harmless locusts. 



Chapter IX. is on "Anatomy and Embryology," and 

 this, according to a statement in the introduction, is by 

 Mr. Packard. Two diagrammatic drawings and several 

 figures illustrate this part of the work; and Mr. C. S. 

 Minot has contributed a few pages on the " fine anatomy," 

 illustrated by plates. 



Chapter X. is on "Metamorphoses." The Rocky 

 Mountain locust requires about seven weeks from 

 hatching to attain full growth, and during that time 

 it passes through six stages. Plate i illustrates these. 

 Though in European migratory species there is a 

 difference of opinion as to whether there are four or five 

 moults, the writers say they have " thousands of mounted 

 and alcoholic specimens of all ages" showing the six 

 stages. " The number of moults may vary according to 

 the amount of nutrition and rapidity of development." 



In Chapter XL on "Invertebrate Enemies," the life- 

 histories of many insects are given, and this part of the 

 work occupies fifty pages. 



Chapter XII., on "Vertebrate Enemies," gives a 

 resume of what is known of the usefulness of birds. Black- 

 birds, prairie-hens, and quail, are found to be good locust 

 destroyers, while a special section is given to stating 

 reasons why the English sparrow should not be introduced. 



Chapter XII I., seventy pages in length, is largely of 

 interest to mechanicians, and deals with " remedies and 

 devices for destruction." Many of the remedies are 

 agricultural operations to be performed at particular 

 times, according to varying circumstances, but the special 

 devices, both protective and for " catching or bagging " 

 eggs and insects are numerous and are illustrated by wood- 

 cuts. The three succeeding Chapters are on "influence 

 of prairie fires on locust increase," "influence of weather 

 on the species," "Effects that generally follow severe 

 locust injury." Then follows a Chapter (XVII.) on the 

 uses to which locusts can be put, in which it is urged they 

 form an abundant and nutritious article of food. " Why 

 should the people of the West, when rendered destitute 

 and foodless by these insects, not make the best of the 

 circumstances, and guard against famine by utilising them 

 as food } " 



The different methods of cooking locusts are entered 

 into, and an account is also given of the use of them by 

 different nations. They were counted as clean animals 



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