KING HERRING 



735 



five per cent of the annual losses to 

 which the herring schools are necessarily 

 liable, from whales, porpoises, seals, and 

 other mammals ; from cod, haddock, 

 mackerel, sharks, and other fishes ; from 

 gulls, gannets, and other birds, and from 

 the thousands of other natural enemies 

 that begin to prey on the herring while 

 it is still in the egg and continue their 

 attacks throughout its entire existence. 



As Huxley has shown, the basis on 

 which the permanency of the herring 

 schools depends is not so much the 

 preservation of a certain percentage of 

 the fish as the destruction of nearly 

 the entire progeny of each female herring 

 each year. If every mature female her- 

 ring lays 20,000 eggs, a very conserva- 

 tive estimate, and if the numbers of her- 

 ring are to remain approximately the 

 same from year to year, then 19,998 of 



the progeny of every mature female must 

 be destroyed before they reach the spawn- 

 ing period; for if more than two out 

 of the 20,000 escape destruction and 

 spawn, then more fish will be produced 

 than are necessary for maintaining the 

 schools. 



Thus many thousand times the number 

 of herring contained in the schools of a 

 given region must be destroyed each 

 year if the average size or strength of 

 those schools is to remain the same. 

 Huxley has summed up the case in this 

 lucid language : 



Man, in fact, is but one of a vast coopera- 

 tive society of herring-catchers, and the larger 

 the share he takes, the less there is for the rest 

 of the company. If man took none, the other 

 shareholders would have a larger dividend and 

 would thrive and multiply in proportion, but it 

 would come to pretty much the same thing to 

 the herrings. 



ECONOMIC LOSS TO THE PEOPLE OF THE 



UNITED STATES THROUGH INSECTS 



THAT CARRY DISEASE * 



By L. O. Howard, Ph. D. 



Chief of the U. S. Bureau of Entomology 



I 



T has been definitely proven and is 

 now generally accepted that ma- 

 laria in its different forms is dis- 

 seminated among the individuals of the 

 human species by the mosquitoes of the 

 genus Anopheles, and that the malarial 

 organism gains entrance to the human 

 system, so far as known, only by the bite 

 of mosquitoes of this genus. It has been 

 proven with equal definiteness and has 

 also become generally accepted that yel- 

 low fever is disseminated by the bite of a 

 mosquito known as Stegomyia calopus 

 (possibly by the bites of other mosquitoes 

 of the same genus), and, so far as has 

 been discovered, this disease is dissem- 

 inated only in this way. 

 ' Further, it has been scientifically dem- 

 onstrated that the common house flv is 



an active agent in the dissemination of 

 typhoid fever, Asiatic cholera, and other 

 intestinal diseases by carrying the causa- 

 tive organisms of these diseases from the 

 excreta of patients to the food supply of 

 healthy individuals ; and that certain spe- 

 cies of fleas are the active agents in the 

 conveyance of bubonic plague. More- 

 over, the tropical disease known as filari- 

 asis is transmitted by a species of mos- 

 quito. 



Furthermore, it is known that the so- 

 called "spotted fever" of the northern 

 Rocky Mountain region is carried by a 

 species of tick; and it has been demon- 

 strated that certain blood diseases may 

 be carried by several species of biting in- 

 sects. The purulent ophthalmia of the 

 Nile basin is carried by the house fly. A 



* From Bulletin No. 78, Bureau of Entomology, U. S. Department of Agriculture. 



