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NA TURE 



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of the United States collects information which may serve 

 a purpose in a war of extermination against the objects 

 of its studies. The volume contains a vast amount of 

 practical information, an extensive series of microscopic 

 sections, chiefly relating to the embryology of insects, zoo- 

 graphical maps of North America, and appendixes bearing 

 upon the subject-matter of the volume. Each destructive- 

 insect is very fully treated of with regard to its biological 

 relations, its distribution, ravages, and methods of preven- 

 tion, all of which are of great interest. A middle section 

 of the volume is occupied with matter which may be de- 

 scribed as pure embryology, and deals with the deepest 

 questions which await the microscopist or the biologist. 

 Thus the formation of the blastoderm, endoderm, meso- 

 derm, and inner germinal cells, the phenomena of in- 

 vagination, the evolution of the brain and ganglionic 

 chain, the philosophy of metamorphosis, and the origin of 

 wings. These matters appear scarcely germane to an 

 Agricultural Department, and it is by no means easy to 

 see how the discussion of such problems can throw 

 the least little ray of light upon economic entomology. 

 Viewed as a pursuit after pure knowledge, and a deep 

 diving after the great mystery of life, these chapters may 

 be considered as a contribution to our speculative know- 

 ledge. As a part of an agricultural report they are 

 as relevant as would be a disquisition upon a fourth 

 dimension or molecular movements in solids. At p. 295 

 is a Genealogy of Insects (Hexapoda), tracing from the 

 Thysanura, followed by a detailed but highly speculative 

 theory of the origin of the Coleoptera and other insect 

 types. " The primitive form of beetle was probably a 

 Staphylinus-like form, with a long narrow body, and rudi- 

 mentary elytra, and carnivorous in habit." Such specula- 

 tions probably are useful to their originator chiefly. We 

 do not in fact deny their biological interest, but they are 

 misleading in such a report as that before us. It is no 

 doubt difficult to draw the line between what is useful and 

 what is not, but in loading an economic report with such 

 matter a door is opened which could scarcely be shut 

 against any biological problem whatever. And yet some 

 sop must be thrown to the scientific inquirer enlisted in 

 the service of a Commission. He perchance would mope 

 and pine if too rigidly confined to the economic side 

 without being allowed to express his views upon deeper 

 and wider problems. There is abundance of matter con- 

 genial to the agriculturist in these pages. It would not 

 be just in the limits of one short article to attempt to 

 review all the subjects of interest brought within the 

 covers of this volume. We select as an example of the 

 work done by the Commission that familiar enemy of our 

 race, the locust ; and we trust room will be found in these 

 columns for a second notice of this work. " If you 

 avoid the destruction of locusts, you will have to forget 

 the welfare of the people : which do you think ought to 

 be thought of first ? Was not therefore Tao-choon wise 

 and good when he said ' in killing insects one saves 

 men?" Good Tao-choon flourished in the reign of Tai- 

 Tzoon (dynasty Tan, from 627 ante till 649 post Christum), 

 and he is still quoted in the Far West as an authority on 

 locust destruction. So far back in point of time and so 

 wide in point of distance do the Commission ransack for 

 information, bringing all to bear upon this war. The 

 Emperor Shen-Tzoon's orders would not perhaps com- 

 mend themselves entirely to the independent voters of the 

 free States. Thus, " whenever locusts leave-desert places 

 to go to populated ones, the local chiefs are obliged to hire 

 poor people and have the eggs destroyed. If all of them 

 should not be destroyed, and the locust therefrom reappear 

 the next year, those commanders will be punished with 

 100 bamboo-rod blows." Again, " Once the locust appears 

 there is no writing to be done for excuses of absence of 

 chiefs, &c. — paper won't help — the commander-in-chief 

 must be present." Evidently high position in the reign 

 of Shen-Tzoon had its duties and responsibilities as well 



as its privileges. The practical and relentless measures 

 recommended are thus described in the same document. 

 " For the purpose of burning the locusts one digs a ditch 

 5 feet deep and 5 feet wide and twice as long. One 

 empties the bags into the fire. As soon as the locust is 

 in, it won't jump out. That's what the poetry means by 

 ' delivering them over to the flames.' Even in old times 

 they knew that if you bury a locust he will creep out 

 again. Therefore the destruction of locusts by fire, as 

 they did in ancient times, is the best." 



The Rock)- Mountain locust (Calop/cnus sprctus) is one 

 out of about 200 species of this prolific family represented 

 in North America. If we run our eyes over the map of 

 North America and set aside all that portion contained be- 

 tween meridians 103 and 117° W. of Greenwich, and from 

 the parallels of latitude 40° to 53°, we have the " perma- 

 nent home" of this insect well before us. It is all 

 considerably elevated, treeless, and arid, thus agreeing 

 to some extent with the locust areas of Eastern Europe, 

 Northern Africa, Asia, Australia, and Central and South 

 America. It includes the greater part of Kansas, Ne- 

 braska, Colorado, Wyoming, Utah, Dakota, Montana, 

 Oregon, Nevada, and extends far southward into Mexico. 

 It is bounded on the north by the tree-bearing regions of 

 British America, on the east by the great wheat-bearing 

 regions of the Eastern States, and on the west by the 

 higher ranges of the Rocky Mountains. This gigantic 

 area comprises 300,000 square miles, and the annual rain- 

 fall is under twenty inches. It is all elevated, dry, and 

 bracing, and is known physically as the arid region. It 

 is not a wheat-growing area. Here the locust finds a 

 permanent home, free from diseases, and suitable for 

 breeding, and it is from these regions that, about once in 

 eleven years, or at the minimum period of sun-spots, ex- 

 cursions are made and devastation is wrought. Still, 

 while the whole of the permanent region is favourable to 

 the locust, there are in reality but few portions of it that 

 are adapted to its greatest increase. The largest and by 

 far the most important of these specially favourable areas 

 is that of Central Montana and portions of the British 

 Possessions immediately to the north. The next in im- 

 portance is that of which the Snake River Valley is the 

 centre, while a third locality is that of Southern Utah 

 and parts of adjoining States. We must not pause to 

 consider the prodigious and terrible armies with their 

 devastating effects, " darkening the sun," and " piled up 

 in ' windrows ' for miles in length." Such narrations are 

 highly entertaining, but may be "taken as read "by most of 

 the readers of Nature. With reference to the treatment 

 of this evil, it is hoped that cultivation will restrict the 

 breeding area gradually but surely, and that the changes 

 of climate which follow the husbandman and timber 

 planter may also act advantageously. The active methods 

 consist in digging trenches, sweeping the locusts into 

 them, and burning them. This is best done when the 

 creatures are in a torpid condition at or before sunrise. 

 Harrowing the ground and processes of cultivation are 

 useful in destroying eggs and larva?. The noise of mus- 

 ketry and artillery prevents swarms from alighting, and is 

 frequently employed for this purpose, as are also fires with 

 damp weeds thrown upon them so as to cause dense 

 clouds of smoke. Marching locusts may be arrested by 

 strips of tin resting against posts or nailed to walls, as 

 they cannot climb over such smooth surfaces. Other 

 methods are referred to as having been published in pre- 

 vious reports of the Commission, but on the whole the 

 means proposed and adopted are of that simple sort 

 which would be suggested rather by common sense than 

 by any profound knowledge of the creatures' habits. 



In this respect the Commissioners have been more for- 

 tunate in their study of some of the other insect pests. 

 One correspondent writes with regard to locusts : — 

 " They marched uninterruptedly through the village of 

 Colesberg (Cape Colony), over walls and houses, and 



