.ttS2 
 
 £sB«(t 
 
 SB 933 
 .H82 
 Copy 1 
 
 THE ECONOMIC STATUS OF INSECTS 
 
 AS A CLASS. 
 
 By L O; HOWARD. 
 
 Address of the Eetieing Peesident of the Biological Society 
 OF Washington, Deliveeed January 18, 1899. 
 
 [Beprinted from SCIENCE, N. S., Vol IX., No. S16, Pages S33-i^7, 
 February 17, 1899. } 
 

 .3 1^- 
 D. of u, 
 
iReprinted from SCIENCE, N. S., Vol. IX., No. 216, 
 Pages 233-U'^, February 17, 1899. '\ 
 
 THE ECONOMIC STATUS OF INSECTS AS A 
 CLASS."^ 
 
 The popular conception of insects in gen- 
 eral is undoubtedly that they are injurious. 
 Many writers, it is true, have pointed out 
 the benefits derived from insects, but we 
 think of their damage to crops and of their 
 annoyance to man and animals, and this as- 
 pect of the subject is at once apt to prepon- 
 derate in our minds. It is more than 80 
 years since Kirby and Spence contrasted 
 the injuries caused by insects with the bene- 
 fits derived from them, and it has not l>een 
 comprehensively done since. In the mean- 
 time, whole groups of important injuries 
 have been developed and whole classes of 
 beneficial work have been discovered. 
 Moreover, the tendency of modern thought 
 has not taken this direction. The biologic 
 taxonomic and phylogenetic, and other as- 
 pects of large groups of forms of life have 
 been considered to the exclusion of the eco- 
 nomic aspect, and even where this side has 
 attracted attention investigators have con- 
 fined themselves to specific problems and 
 have not generalized. It may be interest- 
 ing, therefore, once more to contrast the in- 
 jurious insects with the beneficial ones in an 
 effort to gain a clearer idea of the status of 
 the group in its relations with man. 
 
 In abroad way, we may consider the sub- 
 ject under the following heads : 
 
 * Address of the retiring President of the Biological 
 Society of Washington, delivered January 18, 1899. 
 
2" 
 
 Insects are injurious : 
 
 1. As destroyers of crops and other val-- 
 uable plant life. 
 
 2. As destroyers of stored foods, dwell- 
 ings, clothes, books, etc. 
 
 3. As injuring live stock and other useful 
 animals. 
 
 4. As annoying man. 
 
 5. As carriers of disease. 
 Insects are beneficial : 
 
 1. As destroyers of injurious insects. 
 
 2. As destroyers of noxious plants. 
 
 3. As pollenizers of plants. 
 
 4. As scavengers. 
 
 5. As makers of soil. 
 
 6. As food (both for man and for poultry,, 
 song birds and food fishes) and as clothings 
 and as used in the arts. 
 
 DESTROYERS OF CROPS AND OTHER USEFUL 
 PLANTS. 
 
 In the present balance of nature one of 
 the chief functions of insect life is to keep 
 down superabundant vegetation. Almost 
 every kind of plant has its insect enemies, 
 and has had such enemies for many thous- 
 ands of years. So soon as man began to 
 make an effort to upset nature's balance by 
 cultivating certain plants at the expense of 
 others he encountered nature's opposition 
 by means of the increase of insect enemies 
 of the particular plant cultivated, and al- 
 most as early as there is any record of agri- 
 culture in literature there is also mention 
 of the destruction to crops caused by insects. 
 Witness the writings of the prophet Joel^ 
 who might almost be termed an agricul- 
 tural pessimist. 
 
 At the present time almost every culti- 
 vated crop has not only its thousands upon 
 
tTiousands of individual insect enemies, but 
 it is affected by scores and even hundreds of 
 species. A mere tabulation of the insect 
 enemies of the apple already recognized in 
 this country shows 281 species, of clover 82 
 species, and of so new a crop as the sugar 
 beet 70 species. The insects of the vine, of 
 the orange, of the wheat crop, and, in fact, 
 of all of our prominent staples, show equallj' 
 startling figures. 
 
 The actual damage which is done by in- 
 sects in this way is difficult to express. 
 Many attempts have been made by writers 
 on economic entomology to express it in 
 money values. For example, it was esti- 
 mated by the late Professor Rilej' that the 
 average annual damage to cultivated crops 
 by injurious insects in the United States 
 amounted to three hundred millions of dol- 
 lars. The loss from the ravages of one 
 species alone, the chinch bug, during one 
 year was estimated at sixty millions of 
 dollars. While it is true that the combined 
 losses of individual growers might reach 
 such enormous sums as these, there is an 
 element in the total loss which we must 
 not fail to take into consideration, and that 
 is the enhanced value of the portion of the 
 crop which remains. Even in tlie case of 
 an individual a man may lose, for example, 
 half of his crop through the work of the 
 chinch bug, and yet, through widespread 
 damage b}' this insect, the money value of 
 the portion harvested may reach an amount 
 almost as great as would have been gained 
 through the low prices of a successful year 
 of no insect damage As this applies to an 
 individual, it applies much more stronglj^^ 
 to a State or to the country at large, so that 
 even in the year when the grain crop of 
 
the country was said to liave been damaged 
 to the extent of sixty millions of dollars 
 it is safe to say that the total price gained 
 for the crop was as great as it would other- 
 wise have been. These estimates of dam- 
 age, therefore, would much better be ex- 
 pressed in terms of bushels, or some other 
 measure, than in money value. 
 
 It is this aspect of our subject, the dam- 
 age done by injurious insects to agriculture, 
 that has given rise to the comparatively 
 new branch of applied science which we 
 now know as economic entomology, and 
 which, although originating in Europe, has 
 been encouraged to such an extent in our 
 own country, owing partly to our greater 
 necessities and partly to our practical turn 
 of mind, that it is safe to say that at present 
 America leads the rest of the world in this 
 direction. 
 
 It is undoubtedly true that this enormous 
 injury to crops is the chief item in a general 
 consideration of the injuries brought about 
 by insects. 
 
 AS DESTROYERS OF STORED FOODS, DWELLINGS, 
 CLOTHES, BOOKS, ETC. 
 
 It is safe to say that there is hardly any 
 product of man's ingenuity, hardly one of 
 the thousands of useful materials upon 
 which depend his comfort and happiness, 
 which is not damaged, directly or indirectly, 
 by insects. The timbers of which his 
 dwellings are built, nearly all of his house- 
 hold utensils, his garments, practically 
 everything which he uses as food, many of 
 the liquids used as drink, his books, the 
 ornaments with which he surrounds himself, 
 the medicines which he takes when sick, 
 the very tobacco with which he solaces him- 
 
■self— all are destroyed or injuriously af- 
 fected by insects. There is, perhaps, one 
 group of exceptions, and that is those articles 
 which are composed wholly of metal, and 
 yet even here insects may occasionally play 
 an injurious part, since instances are on 
 record of the destruction of lead pipes by 
 insect larvaj, and the perforation of the 
 metal linings of water tanks by small 
 beetles. 
 
 Such injuries to human products are more 
 frequent and serious in tropical regions than 
 in temperate zones, but even here insects 
 of this nature cause very serious inconven- 
 ience and great annual loss. It will answer 
 our purpose, perhaps, to list some of the 
 varying substances which are damaged in 
 this way, to get an ideaof their almost uni- 
 versal character: Ham, cheese, salted 
 fish, butter, lard, dried mushiooms, rye 
 bread, sweetmeats and preserves, powdered 
 coffee, almonds and other nuts, raisins, 
 breakfast foods, chocolate, ginger, rhubarb, 
 black pepper, vinegar, sugar, wines, canned 
 soups, tobacco, snuff, licorice, peppermint, 
 aromatic cardamon, aniseed, aconite, bella- 
 donna, musk, opium, ginseng, chamomile, 
 boneset, hides, shoes, gloves and other 
 leather articles, furniture, carpets, drawings 
 and paintings, paint brushes, gun wads, 
 combs, etc., made of horn ; bay, oats, straw, 
 willow baskets, ax handles, ladders, wheel 
 spokes and all sorts of agriculural imple- 
 ments with wooden handles, barrels, wine 
 casks, corks of wine bottles, sheets of cork, 
 natural history collections, including skele- 
 tons and mummies, and even Persian insect 
 powder ! The mention of this well-known 
 insecticide reminds one of the latest discov- 
 ery, which is that certain flies in California 
 
breed in the crude petroleum pools in the 
 vicinity of oil wells, a fact which is almost 
 paradoxical in view of the extensive use of 
 petroleum as an insecticide. 
 
 AS INJURIOUS TO LIVE STOCK AND OTHER 
 USEFUL ANIMALS. 
 
 Every species of animal which has be- 
 eome domesticated and is of value to man 
 possesses its insect parasites and enemies. 
 These in manj^ cases are the same specie& 
 which aifect man and which we will men- 
 tion in the next section ; others are specific 
 to the animals or groups of animals which 
 they affect. Horses, cattle, sheep, all 
 possess insect enemies which are not only 
 very deleterious to their health, but fre- 
 quently cause their death in numbers. 
 
 The disgusting bot fly of the horse, whose 
 maggots live in incredible numbers in the 
 stomach and intestines of this noble friend 
 of the human race ; the bot fly of the ox, 
 which causes innumerable sores on the 
 backs of cattle and by its perforations ruins 
 their hides for commercial use ; the bot fly 
 of the sheep, which inhabits the nasal and 
 orbital sinuses of the sheep and produces 
 insanity and death — ^will instantly be re- 
 called by those who are familiar with stock 
 raising, while hundreds of other species^ 
 some in no less degree, as the horn fly, the 
 numerous gad flies, including the Tsetse fly 
 of Africa, the screw worm fly of our South- 
 western country, unite to make the lives of 
 domestic animals a burden to themselves 
 and a trial and a loss to their owners. 
 
 An interesting attempt was made some 
 years ago by a prominent Western agri- 
 cultural newspaper, TJie Farmers'' Review, to 
 estimate approximately the pecuniary loss 
 
from the attacks of a single one of these 
 insects — the ox hot fly, or ox warble — on 
 the cattle received at the Union Stock 
 Yards, of Chicago. It was estimated that 
 50 per cent, of the cattle received each year 
 are affected. The number of cattle received 
 at the yards during six months of the year 
 1889 was 1,335,026; the average value of 
 the hide was |3,90 ; the usual deduction for 
 hides damaged by the ox warble was one- 
 third. Estimating at less than one-third, say 
 $1.00, the actual loss during six months on 
 hides alone was $667,513. When to this 
 was added the loss for depreciation in value 
 and lessened quantity of beef, the loss for 
 -each infested animal v/as put at $5.00, a 
 very low estimate, indicating the total loss 
 from the animals in the Union Stock Yards, 
 of Chicago, for a period of six months of 
 $3,336,565. 
 
 AS ANNOYING MAN. 
 
 There are very few regions of the habit- 
 able globe where man is not personally 
 subject to more or less annoyance b}' in- 
 sects. In this part of the world we natu- 
 rally think at once of mosquitoes, house flies, 
 fleas, and of a certain other species which 
 it will not be necessary to name. 
 
 A susceptible individual some years ago 
 wrote to the Department of Agriculture 
 and said that he had come over from the 
 old country and settled in New Jersey, but 
 that the mosquitoes bothered him so greatly 
 that on the advice of friends he moved to 
 northern New York. Here he found that 
 during a certain portion of the year black 
 flies made life unendurable ; thereupon he 
 packed his household effects and moved to 
 North Carolina. Here, however, in the 
 
summer months red bugs, or jiggers, both- 
 ered him to such an extent that he feared 
 he would go crazy, and in this desperate 
 condition he applied to this office to learn 
 whether there existed in the United States 
 a locality where a sensitive individual could 
 find peace from attacks of insects. He said 
 that he had been told that in the Western 
 eountrj^ the buffalo gnat was greatly to be 
 feared, while certain other biting flies would 
 be sure to keep him in a constant state of 
 dermal irritation ; that further south he 
 knew that peaceful nights were to be gained 
 in the summer time only under the protec- 
 tion of mosquito bars. He had thought of 
 the newly developing country of Alaska, but 
 had recently seen an account in the news- 
 paper of the ferocity of the Alaskan mos- 
 quitoes, which had practically destroyed his 
 last hope. 
 
 Accustomed as most of us are to the mos- 
 quitoes of temperate North America, we 
 hardly realize the impression which they 
 made upon the early English travellers. A 
 story told by Kirby and Spence, to the 
 effect that Mr. Weld in his travels relates 
 from General Washington that in one place 
 the mosquitoes were so powerful as to pierce 
 through his boots, has always excited my 
 interest and curiosity, and I recently took 
 the trouble to consult the original publica- 
 tion, which is ' Isaac Weld's Travels through 
 North America, 1795-1797,' London, 1799. 
 In speaking of Skenesborough, in northern 
 New York, Mr. Weld dilates upon the 
 number and ferocit}^ of the mosquitoes, and 
 makes use of the following words: " Gen- 
 eral Washington told me that he never was 
 so much annoyed by mosquitoes in any 
 part of America as in Skenesborough, for 
 
9 
 
 that they used to bite through the thickest 
 boot." ISTow, knowing that the boots of 
 those days were very thick and that the 
 mosquitoes of that time must have been 
 structurally identical with those of to-day, 
 there arises instantly a question of veracity 
 between Mr, Weld and General Washing- 
 ton ; and as we know from Dr. Weems' 
 veracious historj' that General Washington 
 was so constituted that he could not tell a 
 lie, it looks very much as though Mr. Weld, 
 like many another English traveller who 
 has written a book on his return home, has 
 been inclined to overstate the truth. 
 
 In these days of comparative personal 
 cleanliness some of the most disgusting of 
 the insect annoyers of man have dropped out 
 of sight. The lice, which in former days 
 were common in all classes of society, from 
 king to peasant, are now comparatively un- 
 known. The itch disease, which carried off 
 many a famous character in history, is 
 equally rare. That it still persists, how- 
 ever, is shown bj^ an occasional case re- 
 ported in medical journals. For example, 
 Dr. Robert Hessler, of Indianapolis, re- 
 ported in 1892 a case in his own practice 
 of typical Norway itch in which the itch 
 mites were present in the skin of the patient 
 in enormous numbers. A rough estimate 
 showed seven million eggs and two million 
 mites. 
 
 Those of us who live in a reasonably civil- 
 ized way are confined, in our experience of 
 annoying insects, largelj^ to the forms men- 
 tioned in our opening paragraph, namely, 
 mosquitoes and house flies and rarely fleas ; 
 but a glance through the medical literature 
 reveals the existence of more or less fre- 
 quent cases of such a nature that they are 
 
10 
 
 little less than horrible. Prominent among 
 these are the cases of so called Myasis, and 
 especially those resulting from the attacks 
 of the screw worm fly, Compsomyia macel- 
 laria. 
 
 Residents of temperate regions are fortu- 
 nate as compared with those of tropical 
 regions in respect to the personally annoy- 
 ing insects. Our troubles from these indi- 
 vidually insignificant causes are intensified 
 to a degree in warmer countries, where the 
 comfort of the individual absolutely depends 
 upon the adoption of measures, always dif- 
 ficult and frequently impracticable, to ex- 
 elude insects from his person and from his 
 food. This is so well known in these days 
 of numerous books of travel that I will 
 close this aspect of our question simply 
 with a quotation from a poet of the Indies^ 
 written many years ago : 
 
 " On every dish the booming beetle falls, 
 
 The cockroach plays, or caterpillar crawls : 
 
 A thousand shapes of variegated hues 
 
 Parade the table and inspect the stews. 
 
 To living wal's the swarming hundreds stick, 
 
 Or court, a dainty meal, the oily wick ; 
 
 Heaps over heaps their slimy bodies drench, 
 
 Out go the lamps with suffocating stench. 
 
 When hideous insects every plate defile, 
 
 The laugh how empty, and how forced the smile !'* 
 
 AS CARRIERS OF DISEASE. 
 
 Manson's demonstrated transmission of 
 the filaria diseases of the East (elephan- 
 tiasis, chyluria and lymph scrotum) by in- 
 sects ; the discovery by Salmon and Smith 
 of the carriage of the germ of Texas fever 
 by the well known Southern cattle tick ; 
 the discovery by Koch of the fact that the 
 Tsetse fly of Africa is so destructive to 
 animals, not by its bite alone, but by carry- 
 
11 
 
 5ng into the circulation of the animal that 
 it attacks the micro-organisms of disease ; 
 the demonstration by Howe and others of 
 the previously suspected fact that the puru- 
 lent conjunctivitis of the Egyptians is spread 
 •by the house fly ; the partly proven hypoth- 
 esis of Manson and Grassi of the relation 
 existing between mosquitoes and malaria; 
 the circumstantially proven carriage of the 
 germs of Asiatic cholera and typhoid fever 
 by flies ; the demonstration claimed by 
 Finlay of the carriage of a mild type of 
 yellow fever by mosquitoes ; the suggestion 
 by Hubbard that the ' pink eye ' of the 
 South is spread by Hippelates; the well- 
 recognized fact among the Europeans of the 
 Fiji Islands that without a veil a serious 
 native eye disease will spread through the 
 medium of gnats ; the suggestion by Symond 
 of the agency of fleas in the spread of 
 the bubonic plague ; the demonstration of 
 anthrax bacilli in malignant pustules in 
 human beings, caused by the bite of Taba- 
 nus and Stomoxys — all indicate an impor- 
 tant and very injurious function of insects 
 practically unsuspected until comparatively 
 recent years. It is, in fact, a rapidly in- 
 creasing field of investigations, the possi- 
 bilities of which cannot be accurately estab- 
 lished at the present time. It is, however, 
 not a field which should be left entirely to 
 the medical bacteriologist ; the entomolo- 
 gist should have a share. The life histories 
 and habits of the insects concerued in the 
 damage should be thoroughly understood, 
 since it is not impossible that otherwise the 
 medical investigators may find themselves 
 arriving at perhaps unwarranted conclu- 
 sions. For example, it is a fact probably 
 unknown to the medical men who may be 
 
12 
 
 strongly impressed by the suggested car- 
 riage of tj'^phoid germs by flies, that the 
 house fly, so common in our dining rooms, 
 does not breed in and rarely visits human 
 excrement, while those other kinds of flies, 
 which do so breed, are rarely attracted to 
 articles of food used by human beings. In 
 the crowded and unnatural conditions of 
 army camps, however, and especially where 
 cavalry regiments are stationed, so that 
 there are great amounts of horse manure, 
 the house fly may breed in such enormous 
 numbers as to render of verj likely occur- 
 rence a departure from the normal food 
 habits of the adult. 
 
 Enough has been shown, however, to em- 
 phasize the potentiality of this phase of 
 insect injury. 
 
 BENEFITS 
 AS DESTROYERS OF INJURIOUS INSECTS. 
 
 The economic bearings of insect enemies 
 of insects are very great, and perhaps this 
 is, all things considered, the most important 
 of the beneficial function of insects as a 
 class. 
 
 In the eternal warfare of organism upon 
 organism, in the perpetual strife of species, 
 one preying upon another and that upon a 
 third, the complications of relations of 
 forms which determine the abundance of 
 one species and the scarcity of another are 
 nowhere more marked than among the in- 
 sects. In fact, to the student of insects who 
 has followed out even a single chain of these 
 inter- relationships the thought must neces- 
 sarily come that upon its organic environ- 
 ment, and especially upon its relations with 
 its living neighbors of the animal kingdom, 
 depend the chances of a species not only for 
 
13 
 
 increase, but for survival almost to no lesser 
 degree than upon its inorganic environment. 
 Temperature is the great factor which con- 
 trols the geographical distribution of life, 
 and temperature ia at the back of all these 
 apparent living first causes which control 
 the abundance of a species in a given region, 
 provided we trace them far enough. Yet 
 these living causes, themselves aifected bj' 
 other living causes in an almost endless 
 chain, sometimes, to all appearance, dwarf 
 even temperature as a controlling factor. 
 
 There is not a species of insect that has 
 not its natural enemies in the guise of other 
 insects; there is not one of these other in- 
 sects which has not its own insect foes. 
 From a single species of Bombycid moth, 
 the larvae of which frequently damage 
 forests in Europe to an alarming extent, 
 there have been reared no less than sixty 
 species of hymenopterous parasites. From a 
 single caterpillar of Plusia brassicce have been 
 reared 2,528 individuals of a little hymen- 
 opterous parasite, Cojndosoma truncatellum.-^ 
 
 Outbreaks of injurious insects are fre- 
 quently stopped as though by magic by the 
 work of insect enemies of the species. 
 Hubbard found, in 1880, tliat a minute par- 
 asite, Tricliogramma pretiosa, alone and un- 
 aided, almost annihilated the fifth brood of 
 the cotton worm in Florida, fully ninety 
 per cent, of the eggs of this prolific crop 
 enemy being infested by the parasite. Not 
 longer ago than 1895, in the city of Wash- 
 
 * Tliis observation, which for some years 'held the 
 record, ' as the expression is, was made by Mr. Per- 
 gande, of the U. S. Department of Agriculture. Re- 
 cently, however, Professor A. Giard, of Paris, has 
 more than 3,000 specimens of the same parasite reared 
 from a Plusia caterpillar. 
 
14 
 
 ington, more than ninety-seven per cent, of 
 the caterpillars of one of our most important 
 shade- tree pests were destro3'ed by para- 
 sitic insects, tothe complete relief of the city 
 the following year. The Hessian fly, that 
 destructive enemy to wheat crops in the 
 United States, is practically unconsidered 
 by the wheat growers of certain States, for 
 the reason that whenever its numbers be- 
 gin to be injuriously great its parasites in- 
 crease to such a degree as to prevent ap- 
 preciable damage. 
 
 The control of a plant-feeding insect by 
 its insect enemies is an extremely compli- 
 cated matter, since, as we have already- 
 hinted, the parasites of the parasites play 
 an important part. The undue multiplica- 
 tion of a vegetable feeder is followed by 
 the undue multiplication of parasites, and 
 their increase is followed by the increase of 
 hyper parasites. Following the very in- 
 stance of the multiplication of the shade- 
 tree caterpillar just mentioned, the writer 
 was able to determine this parasitic chain 
 during the next season down to quaternary 
 parasitism. Beyond this point, true internal 
 parasitism probably did not exist, but even 
 these quaternary parasites were subject to 
 bacterial or fungus disease and to the at- 
 tacks of predatory insects. 
 
 The prime cause of the abundance or 
 scarcity of a leaf-feeding species is, there- 
 fore, obscure, since it is hindered by an 
 abundance of primary parasites, favored by 
 an abundance of secondary parasites (since 
 these will destroj'^ the primary parasites), 
 hindered again by an abundance of tertiary 
 parasites, and favored again by an abun- 
 dance of quaternary parasites. 
 
 The subject of practical handling of in- 
 
15 
 
 «ect enemies of insects has come into great 
 prominence during the past ten years. The 
 suggestion by the Rev. Dr. Bethune, of 
 Canada, many years ago, of the desirability 
 of importing the European parasite of the 
 wheat midge into America was probably 
 the first published international suggestion 
 of this nature, and, although some subse- 
 quent correspondence between English and 
 American entomologists ensued, no parasites 
 were actually sent over. Later, attempts 
 were made by LeBaron in the case of a 
 parasite of the oyster-shell bark-louse of 
 the apple, and by Professor Riley in the 
 case of a parasite of the plum curculio, to 
 transport parasites from one section of the 
 United States to another, both attempts 
 meeting with some slight success. 
 
 In 1873 Planchon and Riley introduced 
 an American predatory mite, which feeds 
 in this country on the grape vine Phylloxera^ 
 into France, where it became established, 
 but where it accomplished no appreciable 
 results in the way of checking the spread of 
 this famous vine pest. 
 
 In 1874 efforts were made to send certain 
 parasites of plant-lice from England to New 
 Zealand, without recorded results of value. 
 
 In 1880, in an article upon the para- 
 sites of American scale insects, the writer 
 showed that international transportation is 
 especially easy, and especially des^irable in 
 the case of these insects. 
 
 In 1883 Dr. Riley succeeded in importing 
 a common European parasite of the im- 
 ported cabbage worm into tlvis country, 
 where it established itself and has since 
 proved to be a valuable addition to our fauna. 
 
 In 1891 the same distinguished entomol- 
 ogist brought about the importation of one 
 
16 
 
 of the European parasites of the Hessian 
 fly through the assistance of Mr. Fred. 
 Enock, of London. This parasite main- 
 tained itself in this country certainly a& 
 late as 1895, but has accomplished no ap- 
 preciable good, so far as has been ascertained, 
 in limiting the increase of this destructive 
 enemy to wheat. 
 
 All previous experiments of this nature 
 were dwarfed into insignificance by the as- 
 tounding success of the importation of Novms 
 ( Vedalia) cardinalh, a ladybird beetle, from 
 Australia into California in 1S89. This 
 importation was made, as will be remem- 
 bered, by Mr. Albert Koebele, an attache 
 of the Division of Entomology of the United 
 States Department of Agriculture, whose ex- 
 penses, however, were paid out of a fund 
 appropriated to the Department of State, 
 for the purpose of securing a representation 
 Iroui this country at the Melbourne Expo- 
 sition. A California man, the late Mr. 
 Frank McCoppin, happened to be at the 
 liead of the Exposition Commission ; and, 
 while the late Dr. C. V. Riley was endeav- 
 oring in Washington to induce the Depart- 
 ment of State to set aside a sum, from the 
 Exposition fund, for the expenses of Mr. 
 Koebele, representatives of the State Board 
 of Horticultui-e of California were pressing 
 the same facts upon Mr. McCoppin, the 
 head of the Commissioa. These efforts 
 were being made independently and with- 
 out considtation, hence it happened that 
 after Mr. Koebele had succeeded in sending 
 live Vedalias to California, and after these 
 insects, by their rapid multiplication and 
 voracious habits, had absolutely destroyed 
 the cottony cushion scale in the orange 
 groves of the State, a result which prac - 
 
17 
 
 tically saved millions of dollars to Califor- 
 nia, and which attracted the attention of 
 everyone interested in science or agricul- 
 ture, a most unfortunate controversy en- 
 sued between Dr. Riley and the California 
 State Board of Horticulture as to the placing 
 of the credit of carrying out this wonder- 
 fully successful experiment. This contro- 
 versy embittered the last days of both Dr. 
 Riley and Mr. McCoppin, and was the cause 
 of a disturbance of the formerly pleasant 
 relations between the United States Depart- 
 ment of Agriculture and the State Board of 
 Horticulture of California, which has only 
 recently been overcome. 
 
 Following this successful experiment, the 
 same insect, Noviiis cardinalis, was sent to 
 South Africa, where it exterminated the 
 white or fluted scale in that colony. The 
 next year it was sent to Egypt, where it 
 exterminated a congeneric scale insect in 
 the gardens of Alexandria. 
 
 The following year Mr. Koebele, still an 
 agent of the United States Department of 
 Agriculture, was sent with the consent of 
 the Honorable Jeremiah Rusk, but at the 
 expense of the California State Board of 
 Horticulture, to Australia, New Zealand 
 and the Fiji Islands, for the purpose of 
 securing other valuable beneficial insects 
 for importation into California. Thousands 
 of such insects, comprising a number of 
 different species, nearly all, however, of 
 them Coccinellids, or ladybirds, were sent 
 over and established in California. Several 
 of these species are still living in different 
 parts of the State. The overwhelming suc- 
 cess of the importation of Novius cardinalis 
 was not repeated, but one of the insects 
 brought over at that time, namely, Rhizobius 
 
IS 
 
 venfralis, has unquestionably ridden many 
 olive groves of the destructive black scale^ 
 and is to-day present in many other orchards 
 in such numbers that the scale practically 
 makes no headway. 
 
 After this second Oriental trip the rela- 
 tions between the Department of Agricul- 
 ture and the State Board of Horticulture of 
 California became so strained that the Cali- 
 fornia agents of the Department were given 
 their choice by the Honorable Secretary of 
 Agriculture to resign their positions or be 
 transferred to Washington. Mr. Koebele 
 resigned and w^as soon after employed by 
 the then newly established Hawaiian Re- 
 public for the purpose of travelling in dif- 
 ferent countries and collecting beneficial 
 insects to be introduced into Hawaii for the 
 purpose of destroying injurious insects. It 
 is difficult at this time to ascertain the 
 exact results of the more recent portion of 
 this work. Mr. Koebele's own published 
 reports have dealt less with results than 
 with the details of the introduction of in- 
 sects, and anonymous newspaper reports 
 are not to be accepted as scientific evidence. 
 Fortunately, however, one of the collectors 
 of the British Association for the Advance- 
 ment of Science, Mr. R. E. C. Perkins, was 
 in Hawaii during 189(5 and made a report 
 on Mr. Koebele's work to the committee ap 
 pointed by the Royal Society and the Brit- 
 ish Association for investigating the fauna 
 of the Sandwich Islands, which was pub- 
 lished in Nature for March 25, 1897. From 
 this report it appears that the introduction 
 of Coccinella repanda from Ceylon, Australia 
 and China was so successful in the extermi- 
 nation of plant-lice upon sugar cane and 
 other crops as to obviate all necessity for 
 
19 
 
 spraying. The introduction of Crypiolmnus 
 montrouzieri from Australia resulted in the 
 entire recovery of the coflfee plants and 
 other trees which were on the point of be- 
 ing totally destroyed by the scale insect 
 known as Pulvinaria psidii. Eight other 
 introduced species had at the date of writ- 
 ing (November, 1896) been entirely natu- 
 ralized and were reported as doing good 
 work against certain scale insects. A Chal- 
 cis fly, Chalcis obscurata, introduced from 
 China and Japan, multiplied enormously at 
 the expense of an injurious caterpillar 
 which had severely attacked banana and 
 palm trees. Mr. Koebele, when visiting 
 Washington during November, 1898, men- 
 tioned a number of other importations of 
 beneficial insects into Hawaii, about which 
 it is as yet too early to speak. 
 
 A very recent instance of an international 
 importation of striking value is the sending 
 of Novms cardinalis from this country to 
 Portugal, where the white or fluted scale 
 has been checked and in many orchards ex- 
 terminated in the course of a single year. 
 This importation was made by the writer 
 with the invaluable assistance of the Cali- 
 fornia State Board of Horticulture. 
 
 Other experiments in this line are under 
 way. A parasite of certain wax scales, 
 which are abundant and injurious in the 
 South, has been imported by the writer 
 from Italy, with the cooperation of Pro- 
 fessor Antonio Berlese, of the Royal Scuola 
 di Agricoltura di Portici ; while an effort is 
 being made to bring from Europe insects 
 which will prey upon the Gipsy moth which 
 has been so great a plague about Boston ; 
 and other parasites of injurious scale insects 
 in foreign countries are being studied with 
 
20 
 
 the purpose of eventual]}' obtaining their 
 introduction into the United States. 
 
 AS DESTROYERS OF NOXIOUS PLANTS. 
 
 Just as we have shown how important is 
 the role played bj'^ insects in the destruction 
 of cultivated and useful plants, it will be 
 easy to indicate their importance as de- 
 stroyers of weeds and other noxious plants. 
 We need only mention the common and 
 cosmopolitan thistle butterfly {Pijrameis car- 
 dui)^ the equally common milkweed butter- 
 fly {Anosia plexippus), the purslane cater- 
 pillar ( Copidryas gloveri) , the burdock beetle 
 ( Gastroidea c?/awea), and the purslane sphinx 
 moth (Deilephila lineata) to recall to the 
 mind of the experienced entomologist many 
 other species which do similar work. They 
 are here, as in the former case, perhaps the 
 principal agents in preventing the undue 
 increase of any one species of plant, but as 
 we find here not an effort of man to combat 
 Nature, as it were, by increasing the growth 
 and spread of one species at the expense of 
 the others, but the exact opposite, so, here 
 also, to a degree we find Nature arrayed 
 against man, and insects thus play by no 
 means the same part in the destruction of 
 weeds that they do in the destruction of 
 cultivated crops. Nevertheless, they have 
 an important function in this direction, and 
 it is safe to say that the benefit which the 
 agriculturist derives from their work in this 
 way is very great. As long ago as the be- 
 ginning of the century it was pointed out by 
 Sparrman that a region in Africa, which 
 had been choked up by shrubs, perennial 
 plants and hard, half-withered and unpal- 
 atable grasses, after being made bare by a 
 visitation of destructive grasshoppers, soon 
 
21 
 
 appeared in a far more beautiful dress, 
 clothed with new herbs, superb lilies and 
 fresh annual grasses, affording delicious 
 herbage for the wild cattle and game. 
 
 In a similar way Riley has called atten- 
 tion to the fact that after the great grass- 
 hopper invasions of Colorado and other 
 Western States in the years 1874 to 1876 
 there were wonderful changes in the char- 
 acter of the vegetation, the grasshopper dev- 
 astations being followed by a great preva- 
 lence of plants which in ordinary seasons 
 were scarcely noticed. It is true that some 
 of these plants were dangerous weeds, but 
 others were most valuable as forage for the 
 half starved live stock. Moreover, other 
 plants, and especially short or recumbent 
 grasses, took on a new habit and grew lux- 
 uriantly ; one species, for example, Eragrostis 
 poceoides, ordinarily recumbent and scarcely 
 noted, grew in profusion to a height of three 
 and a-half feet. 
 
 An important, but not generally realized, 
 benefit which is derived from the insects 
 maj^ be mentioned under this head, though 
 not strictly belonging here. Kirby showed, 
 75 years ago, that the insects that attacked 
 the roots of grasses, such as wireworms, 
 white grubs, etc., in ordinary seasons only 
 devour so much as is necessary to make 
 room for fresh shoots and the product 
 of new herbage, in this manner maintain- 
 ing a constant succession of young plants 
 and causing an annual though partial reno- 
 vation of our meadows and pastures, " so 
 that, when in moderate numbers, these in- 
 sects do no more harm to the grass than 
 would the sharp-toothed harrows which it 
 has sometimes been obliged to appl}' to hide- 
 bound pastures, and the beneficial operation 
 
22 
 
 of which in loosening the subsoil these in- 
 sect borers closely imitate." 
 
 AS POLLENIZERS OF PLANTS. 
 
 It can no longer he doubted that cross 
 fertilization is one of the very most impor- 
 tant elements in the progressive develop- 
 ment and continued health of the great 
 majority of flowering plants, and, indeed, 
 that it is with some almost a condition of 
 existence. Opposition to this view, at no 
 time especially strong since the publication 
 of Darwin's great work, has become feebler 
 and more feeble until at the present it is 
 not worth considering. 
 
 Comparative experimentation with self- 
 fertilizing and cross-fertilizing plants, re- 
 peated with many species and genera, have 
 shown a superior growth and vitality on 
 the part of those subjected to cross fertili- 
 zation of such a degree as to leave not a 
 semblance of a doubt ; while in individual 
 cases self fertilization has been scientifically 
 shown to even result in a deterioration so 
 marked that it has been compared to poi- 
 soning. 
 
 In this condition of affairs it at once be- 
 comes evident that the good offices of in- 
 sects in this direction are of incalculable 
 importance, since it must be plain that of 
 the natural agencies by which cross- fertili- 
 zation of plants is accomplished insects are 
 far and away the most prominent. Every 
 investigation which has been undertaken 
 of recent years, and activity in this field is 
 increasing by leaps and bounds, has shown 
 the most marvelous adaptations between 
 the structure of flowers and the structure 
 of their insect visitants, all in the line of 
 facilitating or really enforcing the collect- 
 
23 
 
 ing and carriage of pollen bj^ flower- visiting 
 Insects from one plant to another. An esti- 
 mate of the numbers of the species of insects 
 engaged in this work would include the 
 forms belonging to whole families and al- 
 most orders, and if we could imagine the 
 race of flower- visiting insects wiped out of 
 existence the disastrous effect upon plant 
 growth would he beyond estimate. I am 
 not prepared to state that insects benefit 
 plants in this way to such an extent as to 
 overcome the results of the work of the 
 plant- destroying species, but if it were pos- 
 sible to compare in any way the results of 
 these two classes of work it is safe to say 
 that the effect would be surprising. 
 
 We must, therefore, without going further 
 into detail, placf> this pollenization of plants 
 as one of the very most important beneficial 
 functions of insects in their relations to 
 man. 
 
 AS SCAVENGERS. 
 
 Another beneficial function of insects, the 
 importance of which can hardly be overesti- 
 mated, is their value to humanity in doing 
 away with, and rendering innocuous, dead 
 matter of both plant and animal origin. 
 This subject has never been discussed with- 
 out reference to the famous statement by 
 Linnaeus that the offspring of three blow- 
 flies would destroy the carcass of a horse 
 as quickly as would a lion ; and while the 
 exact statement in its details is open to 
 doubt, still it serves to illustrate, in a strik- 
 ing way, the good ofiices of insects, and it is 
 certainly true that after the offspring of the 
 blow- fly have finished with the horse's car- 
 cass this would be left in a much less offen- 
 sive condition than after the departure of 
 the lion. 
 
24 
 
 There are inhabited regions in which the 
 climate is so dry that dead bodies of ani- 
 mals never become offensive, but, by natural 
 mummification, remain simplj^ as cumberers 
 of the earth. In such regions insects play 
 little part. Wherever, however, there is 
 sufficient moisture to produce a natural de- 
 cay, there insects occur in swarms and 
 hasten the destruction of the decomposing 
 mass in a marked degree. Were the bodies 
 of dead animals not destroyed by insects in 
 this way, and, still more, were the destruc- 
 tion of dead vegetation not hastened as it 
 is by the attacks of countless insects, it is 
 perfectly easy to see that the earth would 
 not be inhabitable, its surface would be 
 covered with the indestructible remains of 
 what was once life in some form. 
 
 Large groups of insects, comprising many 
 thousands of species, take part in this in 
 estimable work, and it will probably be un- 
 necessary in order to bring about a realiza- 
 tion of this value to dwell further upon the 
 subject. 
 
 AS MAKERS OF SOIL. 
 
 It is a, fact not generally realized that 
 insects must take an important part in the 
 changes in the character of the soil which 
 are constantly going on. Occurring in such 
 countless millions, as they do, constantly 
 penetrating the soil in all directions, fre- 
 quently dragging vegetation below the sur- 
 face and bringing the subsoil up to the 
 surface, changing the character of the soil 
 humus by passing it through their bodies, 
 and fertilizing the earth by their own death 
 and decay, it is probable that insects are 
 responsible for even more soil change than 
 are the earth worms, which Darwin has 
 placed before us in such an important light. 
 
25 
 
 Insects are found beneath the ground in 
 incredible numbers ; some of them pass 
 their whole life underground, feeding upon 
 roots and rootlets, upon dead and decaying 
 vegetable matter, upon soil humus and 
 upon other insects; many of them have 
 their nests underground, although they get 
 their food elsewhere ; while others hide 
 their eggs or pupse underground. 
 
 The depth to which they penetrate is 
 something surprising ; the minute insects 
 of the family Poduridse have been found 
 swarming literally by the million at a depth 
 of six to eight feet in a stiff clay subsoil. 
 
 AS FOOD AND CLOTHING AND AS USED IN THE 
 ARTS. 
 
 In this role insects play an important 
 part. Insects as food, and their products 
 as clothing, are well known to all. The 
 great silk industry of the world is derived 
 wholly from insects, and almost entirely 
 from a single species, the silkworm of com- 
 merce. 
 
 As food, insects have formed articles of 
 diet for certain savage peoples since the 
 beginning of the human race. Hope, in 
 1842, catalogued forty-six species of insects 
 used as food, and Wallace, in 1854, showed 
 that insects of six different Orders were used 
 as food bj" the Indians of the Amazon. 
 Semi-civilized peoples to-day use certain in- 
 sects as food, as witness the consumption 
 of Corixa eggs by the Mexicans, and a book 
 has been written under the caption ' Why 
 not eat insects ? ' for the purpose of show- 
 ing that many possibilities in the way of 
 dietetics are being ignored to- day. M. de 
 Fontvielle, in addressing the Societe d'ln- 
 sectologie, in 1883, expressed regret that the 
 
26 
 
 attempts made to popularize the use of in- 
 sects as food have made so little progress, 
 and said that we ought not to forget the 
 remark of the Roman Emperor who said 
 that the body of an enemy never tasted 
 bad, and that the banquet of the Society 
 would always lack something so long as 
 there was not placed before them at least 
 some grasshopper farina and fried white 
 worms. 
 
 A single insect, the honey bee, furnishes 
 a notable article of food, and is the basis of 
 a great and world-wide industry. 
 
 As food for poultry, song birds and food 
 fish, insects are indirectly of great benefit 
 to man. Not only do they provide living 
 food for such animals, but Corixa mercenarm^ 
 a water bug, is now being imported by the 
 ton from Mexico into England as food for 
 birds, poultry, game and fish. One ton of 
 these bugs has been computed by Mr. G. 
 W. Kirkaldy to contain 250,000,000 of in- 
 sects (Entomologists' Monthly Magazine^ Au- 
 gust, 1898). 
 
 In the days of pure empiricism in medi- 
 cine, insects were used extensively, and we 
 have only to mention the Spanish fly to 
 show that they are still of some value. 
 
 In the arts, shellac and Chinese white 
 wax, as is well known, are insect products, 
 as also are the formerly greatly used coch- 
 ineal dye and Polish berry dye, the so-called 
 berry in this case being an insect and not a 
 berry. 
 
 The last-named instances are all derived 
 from scale insects, a group of astonishing 
 capacity for multiplication, the commercial 
 possibilities of which are by no means ex- 
 hausted, as I took pleasure in showing in a 
 paper read before the Amer-ican Association 
 
27 
 
 for the Advancement of Science in 1897. It 
 should be noted here, also, that there is 
 good reason to believe that the manna of 
 the Bible, upon which the Children of Israel 
 subsisted while in the Wilderness, was also 
 the secretion of a scale insect. 
 
 SUMMARY OF THE HABITS OF INSECTS. 
 
 After this general account, arranged under 
 the classes of damage and classes of benefits 
 brought about by insects, it will be well to 
 attempt an arrangement of the subject in a 
 somewhat different manner, in order to gain, 
 if possible, some light as to the relative 
 proportion of insects which are injurious or 
 beneficial. 
 
 It will be manifestly impossible to cata- 
 logue the species or the genera in this way, 
 and it will be obvious that a classification 
 from families will be lacking in exactness, 
 since some of the families are very large in 
 number of species and others exceedingly 
 small ; but, taking the groups as a whole, 
 no better and speedier means suggests itself 
 than to summarize the habits by families. 
 
 Another difficulty, however, which arises 
 in such a classification is the fact that some 
 orders are in a much more advanced stage 
 of classification than others, and the force 
 which is given to a familj' as a taxonomic 
 group varies with the views of the latest 
 monographer. Nevertheless, taking only 
 the older and generally accepted families 
 and analyzing habits, we find the situation 
 to be as follows : 
 
 Of 33 families of Hymenoptera, but two 
 are strictly plant- feeding; the Cynipidaj, or 
 gall flies, are in the main injurious to 
 plants, but some forms are parasitic ; nine 
 families are strictly parasitic upon other 
 
2S 
 
 insects ; fifteen are predatory upon other 
 insects ; two, comprising the bees, have no 
 other especial value in their relations with 
 man than as pollenizers of plants, or pro- 
 ducers of honey ; three, comprising the ants, 
 are beneficial as scavengers, but injurious 
 in their other relations. It must be re- 
 membered, however, that at least 27 of the 
 33 families are of the greatest value in the 
 cross- fertilization of plants, in which work 
 the insects of this order perhaps take the 
 lead. 
 
 In the Coleoptera, or beetles, considering 
 82 families, the insects of nine families on 
 the whole are injurious, and of 23 families 
 on the whole are beneficial aa destroying 
 injurious insects ; 10 families are beneficial 
 as scavengers, and 30, or more, mostly small 
 groups of little importance, contain some 
 scavengers and many neutral forms of prac- 
 tically no economic importance, although 
 certain of them visit flowers ; two families 
 contain both injurious and beneficial forms, 
 as well as manj^ that are neutral. 
 
 In the Siphonaptera, or fleas, the species 
 of the single family are parasitic upon 
 warm-blooded animals. 
 
 In the Diptera, or true flies, if we classify 
 the families according to habits of the 
 majority of the species in each, we get ap- 
 proximately : injurious families, 10; preda- 
 ceous families, 11; parasitic family, 1 ; scav- 
 engers, 19. In point of numbers, of indi- 
 viduals in this order, as well as in the 
 Coleoptera, no doubt the injurious will ex- 
 ceed the predaceous ; while in the Diptera 
 the scavengers will probably equal all of 
 the others put together. 
 
 In the Lepidoptera practically all of the 
 60 odd families are injurious through the 
 
29 
 
 damage done by their larvse to vegetation, 
 but here again it must be remembered — and 
 the same comment holds for many of the 
 Diptera which we have just considered — that 
 the adult insects are among the most active 
 and frequent visitors of flowers and have a 
 great and beneficial effect on cross- fertiliza- 
 tion. 
 
 In the Trichoptera the insects of the 
 single family feed upon aquatic plants and 
 have no economic value except as furnish- 
 ing food for food fishes. 
 
 The insects of the single family in the 
 order Mecoptera are indifferent in their 
 economic relations, though probably slightly 
 beneficial. 
 
 In the Neuroptera all of the seven fami- 
 lies are beneficial through their predaceous 
 habits, with the exception of the Sialidse, 
 which, since their larvte are aquatic, may 
 be termed indifferent or neutral, though it 
 has both a beneficial and an injurious rela- 
 tion to food fishes. 
 
 In the Homoptei-a we have nine families, 
 all of which are injurious except that here 
 and there a species has had a commercial 
 value, like the lac and dye insects. 
 
 In the Heteroptera there are 11 fami- 
 lies which are strictly plant feeders ; 8 are 
 strictly predaceous ; 3 are both injurious 
 and predaceous; while the economic value 
 of 13 is more or less doubtful. Most of 
 these last are aquatic and have some value 
 as fish food. 
 
 The insects of the single family of the 
 order Physaptera are injurious. 
 
 In the Orthoptera we have one family of 
 strictly predaceous habits ; one which has 
 a mixed food and is partly injurious and 
 partly beneficial as its species become scav- 
 
30 
 
 eugers ; the habits of 1 family are unknown; 
 while in the 4 remaining families the species 
 are all injurious as destroyers of vegetation. 
 
 The insects of the single family of the 
 order Euplexoptera are probably beneficial 
 as predatory forms and scavengers. 
 
 The single family of the order Malloph- 
 aga is injurious, containing parasites oi 
 birds and mammals. 
 
 In the Corrodentia the habits of the in- 
 sects of the single famil}' are on the whole 
 of little economic importance, though the 
 species are to be classified in the main as 
 scavengers. 
 
 In the Isoptera the forms belonging to 
 the two families are injurious. 
 
 In the Order Plecoptera the species of 
 the single family are practically neutral in 
 their economic relations, although they 
 possess some value as fish food. 
 
 All of the insects of the single family of 
 the order Odonata may be called beneficial ; 
 the adults are predaceous upon other in- 
 sects and are thus strictly beneficial, but the 
 larvae may in a sense be termed injurious, 
 since they are aquatic and prey upon other 
 aquatic insects w^iich themselves may be 
 food for fishes. 
 
 The insects of the single family of the 
 order Ephemerida are of little economic 
 value, except that they are important fish 
 food. 
 
 Lastly, the insects of eight of the fami- 
 lies of Thysanura are beneficial as scaven- 
 gers and soil markers, while some of the 
 species of one family are somewhat harmful 
 from the damage which they do in house- 
 holds. 
 
 Tabulating the facts thus gained we have 
 the following : 
 
31 
 
 Injurious as feeding upon cultivated and 
 useful plants, the insects of 112 families. 
 
 Injurious as parasitic upon warm-blooded 
 animals, the insects of 1 family. 
 
 Beueficial as preying upon other insects, 
 the insects of 79 families. 
 
 Beneficial as scavengers, the insects of 32 
 families. 
 
 Beneficial as pollenizers only, the insects 
 of 2 families. 
 
 Beneficial as forming food for food fishes, 
 the insects of 3 families. 
 
 Of undetermined economic importance, 
 the insects of 49 families. 
 
 Families containing both injurious and 
 beneficial forms, 22. 
 
 The totals are : 
 
 Beneficial, the insects of 113 families. 
 
 Injurious, the insects of 116 families. 
 
 Both, or undetermined, the insects of 71 
 families. 
 
 CONCLUSION. 
 
 And now the question is: Are we any 
 nearer the answer of the query in the title 
 of this paper than we were at the start? 
 We have, perhaps, gained by this summary 
 a clearer idea of the economic importance 
 of the class Insecta, and possibly it may 
 appear by this contrasting method that the 
 benefits derived from insects entirely ofiset 
 their injuries ; but we cannot, in our present 
 stage of enlightenment (and I say it with all 
 reverence), complacently and piously adopt, 
 with the good old I'ector of Barham, the 
 view that insects, with all the lower ani- 
 mals, were created for man's benefit, God 
 permitting occasional injuries, to use Kirby's 
 words, " not merely with punitive views, but 
 also to show us what mighty effects he can 
 produce by instruments so insignificant. 
 
32 
 
 thus calling on us to glorify his power, 
 wisdom and goodness." 
 
 Contrast with this view the view of Pro- 
 fessor Bailey, in one of his charming essaj'S 
 in the volume entitled ' The Survival of the 
 Unlike :' " We are now prepared to admit 
 that this whole question of enemy and 
 friend is a relative one, and does not depend 
 upon right and wrong, but simply upon our 
 own relationships to the given animals and 
 plants. An insect which eats our potatoes 
 is an enemy because we want the potatoes 
 too ; the insect has as much right to the 
 potatoes as we have. He is pressed by the 
 common necessit}' of maintaining himself, 
 and there is every evidence that the potato 
 was made as much for the insect as for the 
 human kind. Dame Nature is quite as much 
 interested in the insect as in man. ' What 
 a pretty bug!' she exclaims ; ' send him 
 over to Smith's potato patch.' But a bug 
 which eats this insect is beneficial ; that is, 
 he is beneficial to man, not to the insect. 
 Thus everj^thiug in nature is a benefit to 
 something and an injury to something; and 
 every time that conditions of life are modi- 
 fied the relationships readjust themselves." 
 
 In these w^ords Bailey, with his accustomed 
 felicity, has expressed the situation admi- 
 rably. Man is but one of the forms of life 
 struggling for existence, at continual war- 
 fare with surrounding forms ; but by virtue 
 of his surpassing intelligence — itself as grad- 
 ually evolved as have been the physical 
 characteristics of any given species — he has 
 overrun the earth, has accommodated him- 
 self to the most unnatural environments ; 
 he has dominated all other species in na- 
 ture ; he has turned to his own uses and 
 encouraged or hastened the evolution of 
 
33 
 
 species useful to him or of useful qualities 
 in such species ; he has wiped out of exist- 
 ence certain inimical forms, and is gaining 
 the control of others. He is the dominant 
 type, and types whose existence and methods 
 of life are opposed to his interests are being 
 pushed to the wall. It is the culmination 
 of a history which has many times repeated 
 itself in past ages. The struggle of other 
 forms of life to accommodate themselves to 
 the conditions brought about by the rapid 
 development of this dominant type is one 
 the most interesting fields of study open to 
 the biologist to-day. It would seem as if, 
 in man's efforts to make the face of the 
 earth his own, all the complicated elements 
 of life were arrayed against him, and the 
 great and ultimate result of the labor of the 
 biologist in his study of the relations of the 
 different forms of life and the laws which 
 govern their development will be to bring 
 about the absolute control of all other life 
 by man. Thus it is not only the economic 
 worker who looks for immediate results of a 
 practical kind from his labor — the scientific 
 agriculturist, the horticulturist, the eco- 
 nomic zoologist, the medical bacteriologist 
 — who should command the respect of even 
 the practical- minded man, but the biologist 
 in whatever field, however restricted it 
 may be, whether he is working towards the 
 understanding of broad principles and gen- 
 eral laws, or whether in some narrow corner 
 of research, he is accumulating material 
 which will help ultimately to lead to wider 
 understandings — all are working helpfully 
 and practically towards the perfect well- 
 being of the human race. 
 
 L. O. Howard. 
 Washington, D. C. 
 
015 793 727 3 •