NA rURE 



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THURSDAY, MARCH 14, 1878 



THE LOCUST PLAGUE IN AMERICA 



The Locust Plague in the United States j being more 

 particularly a Treatise 07i the Rocky Mountain Locust, 

 or so-called Grasshopper, as it occurs East of the Rocky 

 Mountains, with Practical Recommendations for its 

 Destruction. By Charles V. Riley, M.A., Ph.D., State 

 Entomologist of Missouri, &c. With 45 Illustrations. 

 (Chicago : Rand, McNally, and Co., 1877.) 



THE greater part of this treatise has already appeared 

 in the Entomological Reports published annually 

 for some years past by Mr. Riley, as State Entomologist 

 for Missouri, in which the information was given piece- 

 meal from time to time as it was acquired. The whole is 

 now brought together in a connected and systematic form, 

 and we have in it a very complete and valuable treatise 

 on the different kinds of locusts, whether species or varie- 

 ties, which have proved destructive in North America. 

 Ever since the discovery and colonisation of that con- 

 tinent the new settlements have been from time to time 

 subject more or less to scarcities resulting from the 

 invasions or migrations of these insects. These have 

 gradually, however, become scarcer and scarcer, and 

 confined more and more to the interior as the insects 

 retreated before the advancing wave of civilisation and 

 cultivation, until now their ravages do not extend east- 

 wards beyond the i6th or 17th degree of longitude west 

 of Washington ; in other words, the regions lying to the 

 east of the Mississippi are now nearly free from them, 

 and it is only in those lying to the west of that river that 

 their propagation and migrations take place on such a 

 scale as seriously to affect the property and prosperity of 

 the settlers. It is not that the species originally inhabit- 

 ing the eastern coast have been gradually pushed back to 

 the interior, but that the species peculiar to it have been 

 reduced in number in the cultivated districts, and their 

 role has been successively taken up by other species lying 

 more inland as civilisation has gradually advanced. The 

 species on which that mission has now devolved are two 

 or three that have their home and permanent breeding- 

 place in the Rocky Mountains — we say ■permanent in 

 contradistinction to temporary breeding-place, because 

 when they make their migrations, they often rest and 

 breed at its furthest limit, the brood returning in the 

 following year to the country from which their parents 

 came, although not necessarily by the same route. 

 The route by which they have hitherto invaded the 

 countries to the east of their proper home in the Rocky 

 Mountains has been from north-west to south-east. That 

 by which the fresh-bred swarms sprung from the invaders 

 have made their way back again next year, has been 

 from south-east to north-west, but not absolutely in the 

 same line by which their parents came, but either 

 parallel to it or slightly divergent. Their course of 

 invasion has been carefully traced for many years by Mr. 

 Riley and others, and the fact of their return on their 

 footsteps in this way is beyond question ; but it is also 

 beyond doubt that the new brood does not go back so 

 strong or so numerous as their parents came. Their 

 constitution appears to be sapped by the change of 

 Vol. XVII. — No. 437 



climate or condition of life j they are feeble and infested 

 by parasites, so that a large proportion of them die a 

 natural death — a consideration which doubtless explains 

 why the vast swarms which have passed from one country 

 to another in all ages and in all quarters of the globe, 

 seem never to have made good a permanent footing in the 

 country they have invaded ; at all events never in num- 

 bers at all corresponding to the force of the intruders. 

 This is no doubt but small consolation to settlers living 

 on the borders of a locust-stricken land, but it is better 

 than none— they would be still worse off if the locusts 

 were to remain as a permanent incubus instead of only 

 coming occasionally as a ravaging horde. 



Of the amount of injury done by the invading hosts, 

 especially during the more recent invasions of 1873 and 

 following years, Mr. Riley gives a striking account. Where 

 a territory of hundreds of miles in extent is struck with deso- 

 lation in a few days or weeks through the ravages of an 

 insect, it is scarcely possible to speak of it without exaggera- 

 tion, and some qualification will almost certainly have to be 

 made upon any estimate of the amount of damage sup- 

 posed to have been sustained, especially when, as here, we 

 know how little the data on which the estimates are founded 

 are to be relied on. In Great Britain we have now an 

 elaborate machinery by which reliable agricultural returns 

 are obtained ; the land, or most of it, has been measured 

 and mapped out ; the best means are taken to obtain true 

 and correct returns, and when obtained they are checked 

 by competent and trustworthy experts ; so that no error 

 of any magnitude can well creep in without detection. It 

 is otherwise on the prairies west of Missouri. The 

 admirable United States Surveys, although sufficiently 

 perfect and on a sufficiently large scale to answer all 

 general purposes, have no pretensions to such detail as 

 we have adopted in our Ordnance Survey Maps, and no 

 attempt is made to give the acreage of the different plots 

 in cultivation (which, besides, would be useless, as it is 

 an uncertain quantity, varying every year). At the best, 

 therefore, there are no other means of estimating either the 

 amount in cultivation or the amount of damage inflicted 

 on it than an empirical estimate furnished by the farmers 

 themselves, a mode of calculation open to many objections, 

 and requiring much allowance. Still, giving the widest 

 margin, enough remains behind to satisfy the hungriest 

 appetite for startling results. If actual starvation did not 

 come in the locusts' train, poverty and distress did. In 1874 

 the loss to three exposed, although thinly-peopled, states, 

 Wyoming, Dakota, and Montana, is said to have been 

 fifty millions of dollars; and in 1875 it was calculated 

 that about three-quarters of a million of people were 

 made sufferers on a strip of about twenty-five miles broad 

 along the banks of the Missouri, from Omaha to Kansas. 



Mr. Riley gives many statistics on such points. His 

 information regarding the habits of the locusts and their 

 enemies, and the best way of dealing with them, is also 

 ample ; and his scientific descriptions and natural his- 

 tory of the species in all their stages leave nothing to 

 be desired. He even touches upon their value as food 

 either with or without wild honey, and gives the results 

 of his experience as to the best mode of cooking them. 

 During a visit that he paid to this country, some two or 

 three years ago, he brought some dried potted specimen 

 with him ; but thatwas scarcely fair play to the locusts, 



